Dual-band communication satellite system and method

ABSTRACT

Dual-band satellite communication systems and methods are described. A dual-band satellite communication system is described with an array of feeds. The array includes single band feeds and one or more multi-band feeds. The multi-band feeds provide dual-band spot beams. Dual-band spot beams include a first frequency band spot beam and a second frequency band spot beam. A spot beam layout may be provided when a shared reflector for the array of feeds is provided. The first frequency band beamwidth may be smaller than a second frequency band beamwidth and the number of multi-band feeds in the array of feeds may be less than the number of single band feeds.

TECHNICAL FIELD

The present application relates to satellite communications, and moreparticularly to methods and systems for providing dual-band satellitecoverage for a satellite coverage perimeter.

BACKGROUND

A communication satellite may be equipped with multiple communicationpayloads. For example, a communication satellite may be equipped with aC-band frequency payload, a Ku-band frequency payload, and a Ka-bandfrequency payload. Each payload may include a transmitting/receiving(Tx/Rx) antenna subsystem and associated receivers, multiplexers, highpower amplifiers (HPA), and redundancy networks for the respectivefrequency band. In some communication satellites, multiple Tx/Rx antennasubsystems for desired frequency bands may be integrated into a singleTx/Rx antenna subsystem. That is, the integrated Tx/Rx antenna subsystemmay include an array of multi-band feeds for providing multi-bandsatellite coverage.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made, by way of example, to the accompanyingdrawings which show example embodiments of the present disclosure, andin which:

FIG. 1 is a block diagram of a conventional dual-band communicationsatellite system;

FIG. 2 is a block diagram of a dual-band communication satellite systemin accordance with an embodiment of the present application;

FIG. 3 is a chart illustrating a relationship of satellite spot beambeamwidth versus reflector size for example Ka-band and Ku-bandfrequencies;

FIG. 4 is an example spot beam layout for a satellite coverageperimeter;

FIG. 5 is a flowchart illustrating a method for providing a dual-bandspot beam layout plan;

FIG. 6 is a chart illustrating example details relating to the method ofFIG. 5 in accordance with an embodiment of the present application;

FIG. 7 is another example spot beam layout for a satellite coverageperimeter;

FIG. 8 is a flowchart illustrating an example method for providingdual-band satellite coverage using a spot beam layout for a satellitecoverage perimeter;

FIG. 9 is an illustration of a spot beam layout overlaid on a map;

FIG. 10 is a chart illustrating a method for providing a spot beamlayout in accordance with an embodiment of the present application;

FIG. 11 is another example spot beam layout for a satellite coverageperimeter;

FIG. 12A illustrates a first spot beam layout in accordance with anexample embodiment of the present application;

FIG. 12B illustrates a second spot beam layout in accordance withanother example embodiment of the present application;

FIG. 12C illustrates a third spot beam layout in accordance with anotherexample embodiment of the present application;

FIG. 12D illustrates a fourth spot beam layout in accordance withanother example embodiment of the present application;

FIG. 13A is a block diagram of a digital channelizing dual-bandcommunication satellite system in accordance with an embodiment of thepresent application;

FIG. 13B is a block diagram of a Ku-band/Ka-band satellite system formitigating effects caused by heavy rain;

FIG. 14A is an illustration of a Ka-band 4-color and a Ku-band 8-colorfrequency reuse plan for a Ka/Ku-band spot band layout in accordancewith an embodiment of the present application;

FIG. 14B is the spot beam layout of FIG. 4 illustrated using the Ka-band4-color and the Ku-band 8-color frequency reuse plan of FIG. 14A;

FIG. 15 is an illustration of a Ka-band and Ku-band 4-color reusefrequency plan in accordance with an embodiment of the presentapplication;

FIG. 16A is an illustration of a Ka-band 2-color and a Ku-band 4-colorfrequency reuse plan for a Ka/Ku-band spot band layout in accordancewith an embodiment of the present application;

FIG. 16B is the spot beam layout of FIG. 11 illustrated using theKa-band 2-color and the Ku-band 4-color frequency reuse plan of FIG.16A;

FIG. 17 is a frequency plan for mitigating an uplink/downlink frequencyspectrum imbalance issue for a dual Ka/Ku-band satellite communicationsystem in accordance with an embodiment of the present application;

FIG. 18 is a block diagram of a dual-band communication satellite systemin accordance with another embodiment of the present application;

FIG. 19 is another example spot beam layout for a satellite coverageperimeter; and

FIG. 20 is a chart illustrating details for providing spot beam layoutsin accordance with another embodiment of the present application.

Like reference numerals are used in the drawings to denote like elementsand features.

DETAILED DESCRIPTION

In one aspect, the present application describes a satellite system forproviding dual-band satellite coverage using a spot beam layout for asatellite coverage perimeter. The system includes an array of feeds. Thearray includes a plurality of single band feeds. The single band feedsgenerate first frequency band spot beams. The array also includes one ormore multi-band feeds each generating a first frequency band spot beamand a second frequency band spot beam concentric with the firstfrequency band spot beam. The first frequency band spot beam may have adifferent beamwidth than the second frequency band spot beam. The numberof multi-band feeds may be different than the number of single bandfeeds. The system includes a shared reflector for the array of feeds.

In another aspect, the present application describes a method forproviding dual-band satellite coverage using a spot beam layout for asatellite coverage perimeter. The method includes determining areflector size for an array of feeds. The array may generate firstfrequency band spot beams. Each first frequency band spot beam may havea first beamwidth. The method also includes configuring the array toinclude single band feeds to generate the first frequency band spotbeams for the satellite coverage perimeter. Based on the determinedreflector size, the method also includes determining a second beamwidthfor second frequency band spot beams. The second beamwidth may bedifferent than the first beamwidth. The method also includes allocatingone or more feeds in the array as multi-band feeds to generate dual-bandspot beams. Each of the dual-band spot beams may include a firstfrequency band spot beam and a second frequency band spot beamconcentric with the first frequency band spot beam. The number ofmulti-band feeds may be different than the number of single band feeds.

Other example embodiments of the present disclosure will be apparent tothose of ordinary skill in the art from a review of the followingdetailed description in conjunction with the drawings.

Example embodiments of the present disclosure are not limited to anyparticular type of satellite or antenna.

Satellite Overview

Satellites are devices positioned in orbital space that are used forvarious purposes. In one example embodiment, the satellites arecommunication satellites. That is, they are positioned in orbital spacefor the purpose of providing communications. For example, communicationsatellites are designed to relay communication signals between twoend-points (which may be stationary or mobile) to provide communicationservices such as telephone, television, radio and/or internet services.

The satellites may employ a variety of orbital paths around the Earth.For example, satellites may have geostationary orbits, molniya orbits,elliptical orbits, polar and non-polar Earth orbits, etc. Communicationsatellites typically have geostationary orbits. That is, the satelliteshave a circular orbit above the Earth's equator and follow the directionof the Earth's rotation. A satellite in such an orbit has an orbitalperiod equal to the Earth's rotational period, and accordingly mayappear at a fixed position in the sky for ground stations.

Communication satellites are typically spaced apart along thegeostationary orbit. That is, the satellites are positioned in orbitalslots. The satellite operators coordinate their use of orbital slotswith each other under international treaty by the InternationalTelecommunication Union (ITU), and the separation between slots dependson the coverage and frequency of operation of the satellites. Forexample, in at least some example embodiments, the separation betweensatellites may be between 2-3 degrees of orbital longitude. In at leastsome example embodiments, the separation between satellites may be lessthan 2 degrees of separation. The separation of satellites in such amanner allows for frequency reuse for both uplink and downlinktransmission. For example, by separating adjacent satellites by adistance greater than the transmitting beamwidth (i.e., the angle,measured in a horizontal plane, between the directions at which thepower of the beam is at least one-half its maximum value) of an antennaassociated with the ground station for uplink transmission, the samefrequency for the communication signals may be employed to uplink toadjacent satellites with interference at or below the coordinated level.Similarly, if the separated distance between the adjacent satellites isgreater than the receiving beamwidth of the antenna associated with theground station for downlink transmission, the same frequency for thecommunication signals may be employed to downlink from adjacentsatellites with interference at or below the coordinated level.

In order to perform communication functions, the satellite is equippedwith various components. For example, the satellite may include acommunication payload (which may further include transponders, one ormore antennas, and switching systems), engines (to bring the satelliteto the desired orbit), tracking and stabilization systems (used toorient the satellite and to keep the satellite in the correct orbit),power subsystems (to power the satellite) and command and controlsubsystems (to maintain communication with ground control stations).

The transponder of the satellite forms a communication channel betweentwo end-points to allow for communications between the two end-points.The transponder also defines the capacity of the satellite forcommunications.

The antenna of the satellite transmits and receives communicationsignals. More specifically, the antenna is an electronic component thatconverts electric currents (which may be generated by a transmitter) topropagating radio frequency (RF) signal during transmission, andconverts induced RF signals to electric currents during reception. In atleast some example embodiments, the antenna may be associated with anamplifier which may amplify the power of the transmitted or received RFsignals.

The communication signals may be microwave signals. Microwave signalsare RF signals that have wavelengths ranging from as long as one meterto as short as one millimeter. Equivalently, the frequency of the RFsignals may range from 300 MHz to 300 Ghz. More particularly, thecommunication signals are within certain frequency bands of microwavesignals as they are more suited for satellite communications. Forexample, in at least some example embodiments, a satellite may operatewithin the frequency of the C-band defined by the ITU. The C-band is aportion of the electromagnetic spectrum that ranges from approximately 4GHz to 8 GHz. That is, the communication signals are transmitted by andreceived at the satellite within such a frequency range.

In some cases, the satellite may operate within frequencies higher than8 GHz. For example, the satellite may operate within the frequency ofthe Ku-band. The Ku-band is the portion of the electromagnetic spectrumthat ranges from approximately 10 GHz to 18 GHz.

In at least some example embodiments, the satellite may operate withinother high frequencies above the Ku-band. For example, the satellite mayoperate within the Ka-band frequency. The Ka-band is the portion of theelectromagnetic spectrum that ranges from approximately 26.5 GHz to 40GHz (at present, the assigned slots for fixed satellite service (FSS)are 27-31 GHz for uplink and 17.7-21.2 GHz for downlink).

In some examples, the satellite may be configured to operate in morethan one band. In one example, the satellite may be equipped to receiveand transmit signals within the C-band, Ku-band, and Ka-band.

It will be appreciated that the satellites may operate within othermicrowave frequency bands. For example, the satellites may operate inany one of the defined microwave frequency bands ranging in frequenciesfrom approximately 1 GHz to 170 GHz. Examples of other microwavefrequency bands may include the X-band, Q-band, V-band, etc.

Dual-Band Communication Satellite Systems

Reference is now made to FIG. 1, which is a block diagram of aconventional dual-band communication satellite system 100. The dual-bandcommunication satellite system 100 may be configured for Ku-band andKa-band frequencies. A Ku-band system 150 may be separate from a Ka-bandsystem 110. Each of the Ku-band system 150 and the Ka-band system 110may include an antenna system. For example, the Ku-band system 150 mayhave a Ku-band antenna system 154 and the Ka-band system 110 may have aKa-band antenna system 114. The respective antenna systems may includefeed networks and antennas for propagating RF signals for the respectivefrequency bands.

The Ku-band system 150 may include a Ku-band reflector 156. The Ka-bandsystem 110 may include a Ka-band reflector 116. Thus, each of theKu-band system 150 and the Ka-band system 110 may have its ownreflector. The individual reflectors may be optimized for respectivefrequency bands. In some embodiments, the reflectors may have a diameterof 2 to 3 meters. In other embodiments, the reflectors may be any size.The Ku-band sub-system 150 may include a Ku-payload 152. The Ka-bandsubsystem 110 may include a Ka-payload 112.

Reference is now made to FIG. 2, which is a block diagram of a dual-bandcommunication satellite system 200 in accordance with an embodiment thepresent application. The dual-band communication satellite system 200includes a Ka-band payload 212 and a Ku-band payload 252. Although theillustrated dual-band communication satellite system 200 may providespot beams for the Ka/Ku band of frequencies, it will be appreciatedthat aspects of the present application may be implemented for any otherfrequency band pairs, such as C-band/Ku-band and Ka-band/Q-band offrequencies.

The dual-band communication satellite system 200 includes an array offeeds for providing spot beams for a satellite coverage perimeter. Forexample, the array of feeds may include a plurality of single band feeds210 and multi-band feeds 250. The single band feeds 210 may providefirst frequency band spot beams. For example, the single band feeds 210may provide Ka-band spot beams. Although two single band feeds 210 areillustrated, the dual-band communication satellite system 200 mayinclude any number of single band feeds 210.

In some embodiments, each multi-band feeds 250 may generate a firstfrequency band spot beam and a second frequency band spot beam. In thedescription that follows, the first frequency band spot beam and thesecond frequency band spot beam generated by a multi-band feed 250 maycollectively be described as a dual-band spot beam. In some embodiments,the second frequency band spot beam may be concentric with the firstfrequency band spot beam. That is, the first frequency band spot beammay share a boresight with the second frequency band spot beam. In someembodiments, the first frequency band spot beam may be a Ka-band spotbeam and the second frequency band spot beam may be a Ku-band spot beam.

In some embodiments, the first frequency band spot beam may have adifferent beamwidth than the second frequency band spot beam. Forexample, the Ka-band beamwidth may be smaller than the Ku-bandbeamwidth. In some embodiments, the multi-band feeds 250 may includeKa-band and Ku-band waveguides and may combine RF signals from Ka-bandand Ku-band frequencies using associated filters and combining devices.Although one multi-band feed 250 is illustrated in FIG. 2, in someembodiments the dual-band communication satellite system 200 may includeany number of multi-band feeds 250.

In some embodiments, the multi-band feeds 250 may generate multi-bandspot beams. For example, each multi-band spot beam may include a firstfrequency band spot beam, a second frequency band spot beam, and a thirdfrequency band spot beam. The first frequency band spot beam, the secondfrequency band spot beam, and the third frequency band spot beam mayshare a common boresight. That is, each of the spot beams in themulti-band spot beam may be concentric with other spot beams in themulti-band spot beam. As an illustrating example, the first frequencyband spot beam may be an X-band spot beam, the second frequency bandspot beam may be a Ku-band spot beam, and the third frequency band spotbeam may be a Ka-band spot beam. Although the X-band, Ku-band, andKa-band are referenced, the spot beams can be of any other frequencyband. In some other embodiments, the multi-band spot beam may include afourth frequency band spot beam or any number of additional band spotbeams.

In some embodiments, the number of multi-band feeds 250 may be differentthan the number of single-band feeds 210. For example, the number ofmulti-band feeds 250 for providing dual-band spot beams may be less thanthe number of single band feeds 210 for providing single-band spotbeams.

The dual-band communication satellite system 200 may also include ashared reflector 260. For example, the shared reflector 260 may be aKa-band/Ku-band shared reflector. Rather than providing a firstreflector for single band feeds and a second reflector for multi-bandfeeds, each of the plurality of single band feeds 210 and the one ormore multi-band feeds 250 may transmit and receive signals using theshared reflector 260. That is, the shared reflector 260 may propagateand receive RF signals for both Ka-band frequencies and Ku-bandfrequencies. It will be appreciated that the shared reflector 260 may befor any other frequency bands.

In some embodiments, the shared reflector 260 is for at least one singleband feed 210 and for at least one multi-band feed 250. In some otherembodiments, the shared reflector 260 is for each of the plurality ofsingle band feeds 210 and for each of the multi-band feeds 250 in thearray of feeds.

In some embodiments, the dual-band communication satellite system 200may include two or more shared reflectors 260 for propagating andreceiving RF signals for single band feeds 210 and multi-band feeds 250.In some embodiments, a shared reflector 260 may be capable ofpropagating and receiving RF signals for a set maximum number of feeds.As an illustrating example, a shared reflector 260 may be capable ofsupporting six single-band feeds and three multi-band feeds.Accordingly, if the array of feeds were to include twelve single bandfeeds 210 and six multi-band feeds 250, the dual-band communicationsatellite system 200 may include two shared reflectors 260. Although theexample described above implements two shared reflectors 260 for twelvesingle band feeds 210 and six multi-band feeds 250, the system couldinclude any number of single band feeds 210 and any number of multi-bandfeeds 250, and could further include any number of shared reflectors 210for propagating and receiving RF signals for the single band feeds 210and multi-band feeds 250.

In some embodiments, the dual-band communication satellite system 200may include two or more shared reflectors 260 and each shared reflector260 may be the same size as another shared reflector 260. In someembodiments, a first shared reflector may be for propagating andreceiving RF signals for the plurality of single band feeds 210 and asecond shared reflector may be for propagating and receiving RF signalsfor one or more multi-band feeds 250. Accordingly, embodiments of thepresent application may include two or more shared reflectors 260 havingthe same reflector size for propagating and receiving RF signals for anynumber of single band feeds 210 and multi-band feeds 250.

A first frequency band spot beam may have a first beamwidth. A secondfrequency band spot beam may have a second beamwidth. In someembodiments, the shared reflector 260 may have a reflector size. Thereflector size may be based on at least one of a first beamwidth and afirst frequency band spot beam EOC peak-to-edge gain delta requirement.In some embodiments, the reflector size may be based on at least one ofa second beamwidth and a second frequency band spot beam EOCpeak-to-edge gain delta requirement. In some other embodiments, thereflector size may be based on consideration of both the first beamwidthand the second beamwidth. That is, instead of prioritizing the reflectorsize based on a single beamwidth, the reflector size may be based onbalancing the requirements of both the first frequency band spot beam(or first beamwidth) and the second frequency band spot beam (or secondbeamwidth) for achieving a desired spot beam layout for providingdual-band satellite coverage.

Reference is now made to FIG. 3, which is a chart 300 illustrating arelationship of satellite spot beam half-power beamwidth versusreflector size for example Ka-band and Ku-band frequencies. A plot ofthe half-power beamwidth (in degrees) versus reflector diameter (inmeters) for Ku-band downlink at 11 GHz may be illustrated by a firstcurve 310. A plot of the half-power beamwidth (in degrees) versusreflector diameter (in meters) for Ku-band uplink at 14.25 GHz may beillustrated by a second curve 320. A plot of the half-power beamwidth(in degrees) versus reflector diameter (in meters) for Ka-band downlinkat 19.7 GHz may be illustrated by a third curve 330. A plot of thehalf-power beamwidth (in degrees) versus reflector diameter (in meters)for Ka-band uplink at 30 GHz may be illustrated by a fourth curve 340.

In some embodiments, the shared reflector 260 (FIG. 2) may have a fixedsize and the spot beam half-power beamwidth may be inverselyproportional to an operating frequency. For example, as a Ka Tx-bandfrequency (e.g., 17.7 to 22.0 GHz) may be approximately double a KuTx-band frequency (e.g., 10.7 to 12.75 GHz), the natural beamwidth ofKu-band spot beams may be approximately double the natural beamwidth ofKa-band spot beams. Accordingly, in some embodiments, the array of feedsmay include a plurality of single band feeds 210 (FIG. 2) and one ormore multi-band feeds 250 (FIG. 2), where the number of multi-band feeds250 may be less than the number of single-band feeds 210. Even thoughthe number of multi-band feeds 250 may be less than the number ofsingle-band feeds 210, because the shared reflector 260 may have a fixedsize, dual-band satellite coverage may be provided. Although the aboveexample illustrates the beamwidth of Ku-band spot beams beingapproximately double the natural beamwidth of Ka-band spot beams, theKu-band beamwidth may, in some embodiments, be four times Ka-bandbeamwidth, or any other multiple of beamwidth of the Ka-band spot beams.

Spot Beam Layouts

Reference is now made to FIG. 4, which a spot beam layout 400 for asatellite coverage perimeter 480, in accordance with an embodiment ofthe present application. The spot beam layout 400 may include Ka-bandspot beams and Ku-band spot beams. The spot beam layout 400 may beprovided by the dual-band communication satellite system 200 of FIG. 2.The desired satellite coverage perimeter 480 is illustrated with dashedlines and may be a rectangular perimeter. Although the satellitecoverage perimeter 480 is illustrated as a rectangular perimeter, thedesired satellite coverage perimeter 480 may be any other shape orcombination of shapes.

The spot beam layout 400 of FIG. 4 may include first frequency band spotbeams and second frequency band spot beams. For example, first frequencyband spot beams may be Ka-band spot beams and second frequency band spotbeams may be Ku-band spot beams. The spot beam layout 400 of FIG. 4 maybe generated by a plurality of single band feeds 210 (FIG. 2) and one ormore multi-band feeds 250 (FIG. 2).

In some embodiments, the multi-band feeds 250 may each generate a firstfrequency band spot beam (e.g., Ka-band spot beam) and a secondfrequency band spot beam (e.g., Ku-band spot beam). A first frequencyband spot beam and a second frequency band spot beam generated by amulti-band feed 250 may collectively be described as a dual-band spotbeam. In the example illustrated in FIG. 4, the first frequency bandspot beam may have a smaller beamwidth than the second frequency bandspot beam. That is, the first frequency band spot beams are illustratedwith smaller diameter circles than the second frequency band spot beams.

For the spot beam layout 400 of FIG. 4, six multi-band feeds 250 maygenerate six dual-band spot beams. That is, each multi-band feed 250 maygenerate a dual-band spot beam. For example, a multi-band feed 250 maygenerate a dual-band spot beam 414 indicated at a location identified bythe number 14. The dual-band spot beam 414 may include a first frequencyband spot beam 414 a (small circle) and a second frequency band spotbeam 414 b (large circle). Accordingly, a dual-band satellitecommunication system 200 (FIG. 2) may include six multi-band feeds 250,and each of the six multi-band feeds 250 may generate a dual-band spotbeam. Six dual-band spot beams are illustrated in FIG. 4 and areindicated at locations identified by the numbers 10, 12, 14, 27, 29, and31. The locations of the six dual-band spot beams are graphicallyillustrated with small circles being thicker circles.

In addition to the six illustrated dual-band spot beams in FIG. 4, thespot beam layout 400 of FIG. 4 may also include a plurality ofadditional first frequency band spot beams (e.g., Ka-band spot beams).That is, in addition to the first frequency band spot beams indicated atlocations identified by numbers 10, 12, 14, 27, 29, and 31 (discussedabove), a plurality of single band feeds 210 may generate the pluralityof additional first frequency band spot beams at locations indicated bynumbers 1 to 9, 11, 13, 15 to 26, 28, 30, and 32 to 40. Accordingly, 34single band feeds 210 may generate the additional 34 first frequencyband spot beams at locations indicated by numbers 1 to 9, 11, 13, 15 to26, 28, 30, and 32 to 40. For ease of illustration, three firstfrequency band spot beams generated by single band feeds 210 have beenidentified, such as first spot beam 421, second spot beam 422, and thirdspot beam 423. As will be apparent from the present application, ratherthan requiring 40 multi-band feeds 250 for generating the spot beamlayout 400 of FIG. 4, 6 multi-band feeds 250 and 34 single band feeds210 may generate the spot beam layout 400 of FIG. 4.

Each illustrated spot beam may indicate an edge-of-coverage (EOC)contour of a first frequency band spot beam (e.g., first spot beam 421indicates the EOC contour of a Ka-band spot beam). In some embodiments,the EOC contour may be based on a 3 dB (half-power) to 7 dB beampeak-to-edge gain delta. For example, a Ka-band beamwidth, at its 3 dBEOC downlink gain delta level, may be 1.6 degrees. Thus, in the presentexample, a Ku-band beamwidth may be two times the Ka-band beamwidth.

Based on the foregoing discussion, each of the 6 multi-band feeds 250and the 34 single band feeds 210 may receive and transmit RF signalsusing the shared reflector 260 (FIG. 2). As described above, in someembodiments, a shared reflector 260 may be capable of propagating andreceiving RF signals for a maximum number of feeds, where the feeds inthe maximum number of feeds could include any of either the single bandfeeds 210 (FIG. 2) or the multi-band feeds 250 (FIG. 2). Accordingly,two or more shared reflectors 260 may be needed if the number of feedsin the array of feeds exceeds the maximum number of feeds that may besupported by one shared reflector 260.

Some embodiments of the dual-band communication satellite system 200 inthe present application may utilize a fewer total number of reflectorsas compared to a conventional dual-band communication satellite system100 (FIG. 1). In the conventional dual-band communication satellitesystem 100, a specifically sized Ka-band reflector 116 (FIG. 1) may berequired for first frequency band feeds (e.g., Ka-band feeds). Further,a second specifically sized Ku-band reflector 156 (FIG. 1) may berequired for second frequency band feeds (e.g., Ku-band feeds). Incontrast, a dual-band communication satellite system 200 of the presentapplication may include a shared reflector 260 capable of bothpropagating and reflecting RF signals for both single-band feeds 210(e.g., Ka-band feeds) and multi-band feeds 250 (e.g., for generatingKa-band and Ku-band signals). Accordingly, because the shared reflector260 may be capable of servicing either of first frequency band signalsand second frequency band signals, the total number of requiredreflectors for servicing the array of single band feeds 210 andmulti-band feeds 250 may be less than the total number of requiredreflectors in the conventional dual-band communication satellite system100 (e.g., total number of required reflectors including number ofKa-band reflectors 116 and Ku-band reflectors 156). That is, thedual-band communication satellite system 200 of the present applicationmay be optimized to utilize a minimum number of reflectors.

Reference is now made to FIG. 5, which is a flowchart illustrating amethod 500 for providing a dual-band spot beam layout plan in accordancewith an embodiment of the present application. For ease of description,the method 500 may be described with reference to the dual-bandcommunication satellite system 200 of FIG. 2. In some embodiments, thearray of feeds, including the plurality of single-band feeds 210 (FIG.2) and one or more multi-band feeds 250 (FIG. 2), may be selectivelyconfigured for providing the spot beam layout 400 for the desiredsatellite coverage perimeter 480 FIG. 4).

At 502, a first frequency band spot beam layout may be provided. Forexample, the first frequency band spot beams may be Ka-band spot beams.Single band feeds 210 may provide the Ka-band spot beams. As will bedescribed with reference to FIG. 6, the first frequency band spot beamlayout for a desired coverage perimeter 480 may be dependent on aKa-band spot beam EOC diameter (e.g., beamwidth) and based on otherdesign requirements for the Ka-band spot beam.

For example, the first frequency band spot beam layout may initiallyinclude the plurality of first frequency band spot beams numbered from 1to 40 (illustrated in FIG. 4). The first frequency band spot beam layoutmay include contiguous first frequency band spot beams and may providesatellite coverage for the first frequency band for the area within thedesired coverage perimeter 480. In some embodiments, the method at 502may be a preliminary step, as single band feeds 210 may be configured toprovide the plurality of first frequency band spot beams. However, aswill be apparent at the method at 508, one or more of the single bandfeeds 210 may be exchanged for a multi-band feed 250 for providing botha first frequency spot beam and a second frequency spot beam (e.g.,dual-band spot beam).

Once an initial first frequency band spot beam layout is provided, at504, satellite coverage and capacity requirements may be evaluated. Forexample, if an initial first frequency band spot beam layout does notprovide for 100% first frequency band satellite coverage for thecoverage perimeter, the first frequency band spot beam layout designprocess at 502 may be iterated. In another example, the data throughputor capacity requirement for the spot beams may be evaluated. If the datathroughput or capacity requirements are not met, the first frequencyband spot beam layout design process at 502 may be iterated.

If the satellite coverage and capacity requirements are met, at 506,satellite system manufacturing costs may be evaluated. For example, afirst satellite system with greater number of feeds may be moreexpensive than a second satellite system with lesser number of feeds.Accordingly, if a satellite system does not meet cost requirements, thefirst frequency band spot beam layout design process may be iterated.That is, an iterated first frequency band spot beam layout may beprovided by a satellite system utilizing fewer number of feeds, but mayrequire that each first frequency spot beam have increased EOC coverage.In some embodiments, other manufacturing or material related costs forthe dual-band satellite communication system 200 may be evaluated.

Although multiple frequency bands are implemented with multi-band feeds250 (FIG. 2), in some embodiments, it may not be necessary to optimizesignal transmission and reception performance for all frequency bandsinvolved. For example, if multi-band feeds 250 provide a dual-band spotbeam including a Ka-band spot beam and a Ku-band spot beam, in someembodiments, it may not be necessary to optimize the signal transmissionand reception performance for both the Ka-band spot beam and the Ku-bandspot beam. To minimize costs, a multi-band feed 250 may be configured togenerate Ka-band spot beams for optimal Ka-band signal transmission andreception performance, while the multi-band feed 250 may not necessarilybe configured to generate Ku-band spot beams for optimal Ku-band signaltransmission and reception performance. That is, the Ku-band signaltransmission and reception performance may be acceptable, but may not befine optimized.

If the satellite system manufacturing costs are met, at 508, a secondfrequency band spot beam layout may be provided. For example, one ormore feeds in the array may be selected or allocated as a multi-bandfeed 250 for generating a dual-band spot beam (see e.g., dual-band spotbeam 414 in FIG. 4). For example, the method at 502 configured singleband feeds 210 to provide a plurality of first frequency band spotbeams. However, because dual-band satellite coverage may be desired, asubset of the single band feeds 210 may be exchanged for a multi-bandfeed 250 for providing both a first frequency spot beam and a secondfrequency spot beam (e.g., dual-band spot beam). At 508, the array offeeds may now include a plurality of single band feeds 210 and one ormore multi-band feeds 250. At 508, the number of multi-band feeds 250for generating first frequency spot beams may be less than the number ofsingle band feeds 210 that were configured at the method at 502.Overall, the preliminary configuration of the array to include singleband feeds 210 at 502 may be modified at 508.

Referring again to FIG. 4, multi-band feeds 250 may generate dual-bandspot beams at layout location numbers 10, 12, 14, 27, 29, and 31. Usingthe third dual-band spot beam 414 identified by location 14 in FIG. 4 asan example, dual-band spot beams may include a first frequency band spotbeam 414 a (e.g., Ka-band spot beam) and a second frequency band spotbeam 414 b (e.g., Ku-band spot beam). The Ku-band spot beam may beconcentric with the Ka-band spot beam. That is, the Ka-band spot beamand the Ku-band spot beam may be circular and may share a commonboresight. Although the spot beams are described as being circular, insome embodiments, the spot beams may be non-circular; however, the firstfrequency band spot beam 414 a and the second frequency band spot beam414 b may share a common boresight. Because the Ku-band spot beam 414 bmay have a beamwidth that is larger than the Ka-band spot beam 414 a,fewer multi-band feeds 250 for providing dual-band spot beams may berequired for providing dual-band satellite coverage for a desiredcoverage perimeter 480. In some embodiments, when providing a secondfrequency band spot beam layout, dual-band spot beam location(s) may beselected based on desired dual-band satellite coverage requirements. Forexample, the dual-band spot beam location(s) may be selected based onidentification of highly populated regions within the satellite coverageperimeter.

Based on the foregoing discussion, it will be apparent that the method500 at 502 includes a preliminary allocation of single band feeds 210(FIG. 2) for generating first frequency band spot beams. Thereafter, themethod 500 at 508 includes iterating the array allocation of feeds suchthat one or more single band feeds 210 configured at 502 may besubstituted for multi-band feeds 250 at 508. The substituted multi-bandfeeds 250 may still provide the first frequency band spot beam, but mayadditionally provide a second frequency band spot beam being concentricwith the first frequency band spot beam.

Reference is now made to FIG. 6, which is a chart 600 illustratingadditional details relating to the method of FIG. 5 in accordance withan embodiment of the present application. A first portion 602 may relateto a first frequency band spot beam layout 610 and may relate to thefirst frequency band spot beam layout process at 502 (FIG. 5). A secondportion 608 may relate to a dual-band spot beam layout 670 and mayrelate to the second frequency band spot beam layout process at 508(FIG. 5).

In some embodiments, the first frequency band spot beam layout 610 maybe based on a first frequency band beamwidth. For example, the firstfrequency band spot beam layout 610 may be based on a Ka-band spot beamEOC diameter 620. Ka-band spot beams with a determined Ka-band spot beamEOC diameter 620 may be selectively positioned within the firstfrequency band spot beam layout 610 to provide desired Ka-band frequencycoverage. For example, a large first frequency band beamwidth mayprovide first frequency band coverage using fewer first frequency bandspot beams, whereas a small first frequency beamwidth may require morespot beams to provide first frequency band coverage for the same givensatellite coverage area.

In other embodiments, the first frequency band spot beam layout 610 maybe based on Ka-band system parameters 630, such as coverage requirementsand/or EOC, EIRP, and G/T requirements. For example, the first frequencyband spot beam layout 610 may be based on a first frequency band spotbeam EOC peak-to-edge gain delta requirement. If a first frequency spotbeam EOC peak-to-edge gain delta requirement may be relaxed (e.g.,relaxed to range of 8 dB to 10 dB), the first frequency band beamwidthmay be enlarged and the number of single band frequency feeds needed forproviding first frequency band coverage may decrease. Referring again toFIG. 4, the spot beam layout 400 may contain an array of spot beamshaving eight (8) Ka-band spot beams across and five (5) Ka-band spotbeams deep. If the Ka-band spot beam EOC peak-to-edge gain deltarequirement were relaxed, the Ka-band beamwidth may increase and thenumber of Ka-band spot beams for providing Ka-band satellite coverage(e.g., spot beam layout 400 of FIG. 4) for the same given satellitecoverage area may decrease.

In some embodiments, the Ka-band beam EOC diameter 620 may be based onKa-band payload 212 (FIG. 2) parameters or requirements, such as highpower amplifier (HPA) output power requirements and/or front end noisefigure requirements. In some embodiments, the Ka-band beam EOC diametermay be based on Ka-band user terminal parameters, such as dish orreflector size parameters and uplink power parameters. The presentdescription provides a brief listing of Ka-band system and/or payloadparameters; however, other Ka-band related parameters may be taken intoaccount.

Once a Ka-band spot beam EOC diameter (e.g., beamwidth) is determinedfor the first frequency spot beam layout 610, a reflector size 622 maybe determined. That is, based on a required operating frequency (orfrequency range) and the determined first frequency spot beam EOCdiameter, a reflector size 622 may be determined. In some embodiments,the reflector size 622 may be determined based at least in part on thehalf-power beamwidth versus reflector diameter relationship illustratedin FIG. 3.

The second portion 608 may relate to a dual-band spot beam layout 670and may relate to the second frequency band spot beam layout designprocess at 508 of FIG. 5. In some embodiments, the dual-band spot beamlayout 670 may be based on a Ku-band spot beam EOC diameter and adetermination of the number and sequence order of multi-band feeds 250(FIG. 2) in an array of feeds (collectively identified in FIG. 6 as660). The shared reflector 260 (FIG. 2) may be used for propagating andreceiving RF signals for both single band feeds 210 (FIG. 2) andmulti-band feeds 250. Based on the previously determined reflector size622 and the operating frequency (or frequency range) of the Ku-band RFsignals, a Ku-band spot beam EOC diameter may be determined based inpart on the half-power beamwidth versus reflector diameter relationshipillustrated in FIG. 3.

In some embodiments, the dual-band spot beam layout 670 may beiteratively determined based on (1) the number of available multi-bandfeeds 250; (2) identification of high throughput demand areas; and (3)the required second frequency band service coverage area. For example,referring again to FIG. 4, the configuration of the array of multi-bandfeeds 250 generating dual-band spot beams (e.g., identified numericallyat 10, 12, 14, 27, 29, and 31 of FIG. 4) may be chosen based onidentified high throughput demand areas within the satellite coverageperimeter 480 (FIG. 4). In some embodiments, where the number ofmulti-band feeds 250 may be limited, allocated multi-band feeds 250 forproviding dual-band spot beams may be “ear-marked” for the “highest”throughput demand areas. For example, if 8 portions within the satellitecoverage perimeter 480 desire dual-band coverage, but only 6 multi-bandfeeds 250 may be available for generating 6 dual-band spot beams, the 6portions within the satellite coverage perimeter 480 may be “ear-marked”as portions within the satellite coverage perimeter 480 on which amulti-band feed 250 may generate a dual-band spot beam for.

Referring still to FIG. 4, as an illustrating example, Ka-band spotbeams (e.g., small circles) may be configured for high throughput demandor data-intensive areas, whereas Ku-band spot beams (e.g., largecircles) may be for extending data service coverage to areas whereKu-band frequencies may be required (e.g., for servicing lessdata-intensive areas, for mitigating signal fade due to heavy rainconditions, for servicing Ku-only user terminals, etc.). Further,Ku-band spot beams may provide supplemental data coverage capacity.

In some embodiments, the Ku-band spot beam EOC diameter and thenumber/locations of multi-band (or dual-band) feeds (e.g., identified as660) may be based on Ku-band system parameters 650. For example, theKu-band system parameters 650 may include parameters such as coveragerequirements and/or EOC, EIRP, and G/T requirements. Further, theKu-band system parameters 650 may include Ku-band payload requirementssuch as high power amplifier (HPA) output power requirements and/orfront end noise figure requirements. In some embodiments, the Ku-bandsystem parameters 650 may also include Ku-band user terminal parameters,such as uplink power parameters and satellite dish size requirements.The present description provides a brief listing of Ku-band systemand/or payload parameters; however, other Ku-band related parameters maybe taken into account.

Based on the foregoing examples, it will be apparent that one or moremulti-band feeds 250 may generate dual-band spot beams for a dual-bandspot beam layout 670 and a plurality of single band feeds 210 maygenerate first frequency band spot beams for a first frequency bandlayout 610. It will be understood that, in some embodiments, an initialor first frequency band layout 610 may be generated by a plurality ofsingle band feeds 210. However, the number of single band feeds 210generating the first frequency band layout 610 may be adjusted when adual-band spot beam layout 670 may be generated by one or moremulti-band feeds 250. That is, the multi-band feeds 250 may providefirst frequency band spot beams in addition to second frequency bandspot beams. Duplicate first frequency band spot beams generated bysingle band feeds 210 may be removed when multi-band feeds 250 may beconfigured to replace single band feeds 210 in an array of feeds. Forexample, when a first frequency band layout 610 is initially provided,single band feeds 210 may be allocated for generating first frequencyband spot beams at locations identified with numbers 10, 12, 14, 27, 29,and 31 (FIG. 4). However, when the dual-band spot beam layout 670 isprovided, the single band feeds 210 generating first frequency band spotbeams at locations identified with numbers 10, 12, 14, 27, 29, and 31,may be replaced with multi-band feeds 250 for generating the firstfrequency band spot beams (in addition to second frequency band spotbeams) at the aforementioned spot beam locations.

Reference is now made to FIG. 7, which is another example spot beamlayout 700 for a satellite coverage perimeter 780, in accordance with anembodiment of the present application. The spot beam layout 700 mayinclude spot beams for Ka-band and Ku-band frequencies. The spot beamlayout 700 may be provided by the dual-band communication satellitesystem 200. The desired satellite coverage perimeter 780 is illustratedby dashed lines and may be a rectangular perimeter. Although thesatellite coverage perimeter 780 is illustrated as a rectangularperimeter, the desired satellite coverage perimeter 780 may be any othershape or combination of shapes.

The spot beam layout 700 may include first frequency band spot beams andsecond frequency band spot beams. For example, first frequency band spotbeams may be Ka-band spot beams and second frequency band spot beams maybe Ku-band spot beams. The spot beam layout 700 of FIG. 7 may begenerated by a plurality of single band feeds 210 (FIG. 2) and one ormore multi-band feeds 250 (FIG. 2).

In some embodiments, the multi-band feeds 250 may each generate a firstfrequency band spot beam (e.g., Ka-band spot beam) and a secondfrequency band spot beam (e.g., Ku-band spot beam). In the exampleillustrated in FIG. 7, the first frequency band spot beam may have asmaller beamwidth than the second frequency band spot beam. That is, thefirst frequency band spot beams are illustrated with smaller diametercircles than the second frequency band spot beams.

For the spot beam layout 700 of FIG. 7, three multi-band feeds 250 maygenerate three dual-band spot beams. That is, each multi-band feed 250may generate a dual-band spot beam. For example, a multi-band feed 250may generate a dual-band spot beam 715 indicated at a locationidentified by the number 15. The dual-band spot beam 715 may include afirst frequency band spot beam 715 a (small circle) and a secondfrequency band spot beam 715 b (large circle). Accordingly, a dual-bandsatellite communication system 200 (FIG. 2) may include three multi-bandfeeds 250, and each of the three multi-band feeds 250 may generate adual-band spot beam. Three dual-band spot beams are illustrated in FIG.7 and are indicated at locations identified by the numbers 9, 15, and28. For example, a first dual-band spot beam 709, a second dual-bandspot beam 715, and a third dual-band spot beam 728 are illustrated. Thelocations of the three dual-band spot beams are graphically illustratedwith small circles being thicker circles.

In addition to the three illustrated dual-band spot beams in FIG. 7, thespot beam layout 700 of FIG. 7 may also include a plurality ofadditional first frequency band spot beams (e.g., Ka-band spot beams).In addition to the first frequency band spot beams indicated atlocations identified by numbers 9, 15, and 28 (discussed above), aplurality of single band feeds 210 may generate the plurality ofadditional first frequency band spot beams at locations indicated bynumbers 1 to 8, 10 to 14, 16 to 27, and 29 to 40. Accordingly, 37 singleband feeds 210 may generate the additional 37 first frequency band spotbeams at locations indicated by numbers 1 to 8, 10 to 14, 16 to 27, and29 to 40. For ease of illustration, three first frequency band spotbeams generated by single band feeds 210 have been identified, such asfourth spot beam 724, fifth spot beam 725, and sixth spot beam 726. Aswill be apparent from the present application, rather than requiring 40multi-band feeds 250 for generating the spot beam layout 700 of FIG. 7,3 multi-band feeds 250 and 37 single band feeds 210 may generate thespot beam layout 700 of FIG. 7.

The total area having dual-band satellite coverage in the spot beamlayout 400 illustrated in FIG. 4 may be different than the total areahaving dual-band satellite coverage in the spot beam layout 700illustrated in FIG. 7. In some embodiments, when location requirementsfor dual-band satellite coverage change, allocation of multi-band feedsin the array of feeds of a satellite system may correspondingly change.For example, in FIG. 4, six (6) dual-band spot beams may be generatedfor portions of the satellite coverage area where throughput demand maybe high. In contrast, in FIG. 7, three (3) dual-band spot beams may begenerated for portions of the satellite coverage area where differentthroughput demand may be high. The portions of the satellite coveragearea where throughput demand is high in the spot beam layout 400 of FIG.4 may be different than the spot beam layout 700 of FIG. 7.

In some embodiments, when satellite system requirements change, the spotbeam EOC diameter (e.g., beamwidth) may also change. For example, when aKu-band spot beam EOC peak-to-edge gain delta requirement may be relaxed(e.g., relaxed to range of 8 dB to 10 dB), the Ku-band beamwidth may beenlarged, thereby reducing the number of multi-band feeds required toprovide dual-band satellite coverage within the satellite coverageperimeter 780. Accordingly, in FIG. 7, the Ku-band spot beam EOCpeak-to-edge gain delta requirement may be relaxed and the Ku-bandbeamwidth may be 2.2 degrees (as compared to the Ku-band beamwidth of1.6 degrees in the layout 400 in FIG. 4).

Based on the foregoing discussion, the dual-band communication satellitesystem 200 (FIG. 2) of the present application may be a simplified andcost-efficient system for providing dual-band satellite coverage to acoverage perimeter. As discussed with reference to FIG. 2, the dual-bandcommunication satellite system 200 may include an array of feeds forpropagating RF signals. The array of feeds may include: (a) single bandfeeds 210 for providing first frequency band spot beams; and (b)multi-band feeds 250 for providing first frequency band spot beams andsecond frequency band spot beams. Further, the dual-band communicationsatellite system 200 may include a shared reflector 260. Because theshared reflector 260 may be simultaneously used for propagating andreceiving RF signals to and from the single band feeds 210 and themulti-band feeds 250, a first frequency band beamwidth may be differentthan a second frequency band beamwidth. For example, if the firstfrequency band is the Ka-band and if the second frequency band is theKu-band, then the second frequency band beamwidth may be approximatelydouble the first frequency band beamwidth (see examples described inrelation to FIG. 3). Because the Ku-band beamwidth may be larger thanthe Ka-band beamwidth, fewer multi-band feeds 250 may be required forproviding dual-band coverage to a coverage perimeter. Accordingly,features of the dual-band communication system 200 in accordance withthe present application may reduce the overall cost of providing thesystem and may simplify the antenna network and configuration design.For example, multi-band feeds 250 may cost more than single band feeds210. Therefore, embodiments of the present application may use fewermulti-band feeds 250 than single band feeds 210 (e.g., for generatingthe dual-band spot beam layout 400 of FIG. 4, 6 multi-band feeds 250 maybe required, rather than 40 multi-band feeds 250).

Further, as the Ku-band beamwidth may be different than the Ka-bandbeamwidth, embodiments of the present application may not requirecomplex and/or costly feed designs focused on generating the similarspot beam shapes and beamwidths for all frequency bands. That is,embodiments of the present application are not for generating spot beamswith similar shapes or spot beams with similar beamwidths; but rather,the embodiments of the present application account for the difference inbeamwidths for minimizing the number of multi-band feeds for providingdual-band satellite coverage to a coverage perimeter.

Reference is now made to FIG. 8, which is a flowchart illustrating anexample method 800 of providing satellite coverage by a dual-bandsatellite system for a coverage perimeter.

The method 800 may include, at 802, determining a reflector size 622 foran array of feeds. The array of feeds may provide first frequency spotbeams (e.g., Ka-band spot beams). Each of the first frequency band spotbeams may have a first beamwidth. For example, referring again to FIG.4, the first frequency band spot beams may have a beamwidth of 0.8degrees. As previously discussed with reference to FIG. 6, the Ka-bandbeamwidth may be determined based on Ka-band system parameters 630 (FIG.6). Accordingly, the reflector size 622 may be determined based on therequired first beamwidth. In some embodiments, the reflector size 622may be determined based on the graphical relationship illustrated inFIG. 3.

For example, in some embodiments, determining the reflector size for thearray may include determining the first beamwidth based on at least oneof an edge-of-coverage requirement of the first frequency band spotbeams, an equivalent isotropically radiated power (EIRP) requirement ofthe first frequency band spot beams, an antenna-to-noise temperature(G/T) requirement of the first frequency band spot beams, or thetargeted ground terminal size. Further, determining the reflector sizemay also include identifying the reflector size based on the firstbeamwidth (e.g., edge-of-coverage requirement) and a first frequencyband spot beam EOC peak-to-edge gain delta requirement.

At 804, the method 800 may include configuring the array of feeds toinclude single band feeds 210 (FIG. 2) to provide first frequency bandspot beams for a coverage perimeter. For example, single band feeds 210may be configured to provide Ka-band spot beams for the coverageperimeter 480. In FIG. 4, there may be forty (40) Ka-band spot beamsnumbered from 1 to 40. The forty Ka-band spot beams may be arranged inan array that may be eight (8) first frequency spot beams wide and five(5) second frequency spot beams deep. Ka-band spot beams may provideKa-band satellite coverage for the area circumscribed by the desiredcoverage perimeter 480.

At 804, 40 single band feeds 210 may be initially or preliminarilyconfigured to generate first frequency band spot beams. That is,although the method 800 at 804 may provide for configuring the array toinclude 40 single band feeds 210 to generate 40 Ka-band spot beams, at808 (to be described below), one or more of the 40 single band feeds 210may be exchanged or substituted for a multi-band feed 250 (FIG. 2) toprovide a first frequency band spot beam, in addition to a secondfrequency band spot beam.

In some embodiments, an array of feeds may be configured to provide thefirst frequency band spot beams to maximize the area of satellitecoverage perimeter having first frequency band spot beam coverage. Insome other embodiments, the array of feeds may be configured to providefirst frequency band spot beams to localized high throughput demandareas. Thus, the satellite coverage perimeter may not have 100% firstfrequency band satellite coverage.

At 806, based on the determined reflector size 622, the method 800 mayinclude determining a second beamwidth for second frequency band spotbeams. Because a shared reflector 260 may be used for propagating andreflecting first frequency band spot beams and second frequency bandspot beams, based on the relationship that a spot beam half-powerbeamwidth is inversely proportional to an operating frequency, a secondfrequency band beamwidth may be greater than a first frequency bandbeamwidth. For example, as a Ka Tx-band frequency (e.g., 17.7 to 22.0GHz) may be approximately double a Ku Tx-band frequency (e.g., 10.7 to12.75 GHz), the natural beamwidth of Ku-band spot beams may beapproximately double the natural beamwidth of Ka-band spot beams. Aswill be apparent from the description in the present application,because the Ku-beamwidth may be twice as large as the Ka-band beamwidth,the number of Ku-band spot beams that may be required to provide Ku-bandsatellite coverage over an area circumscribed by a coverage perimeter480 may be less than the number of Ka-band spot beams required toprovide Ka-band satellite coverage over an area circumscribed by thecoverage perimeter 480.

At 808, the method 800 may include allocating one or more feeds in thearray as multi-band feeds to provide dual-band spot beams. Each of thedual-band spot beams may include a first frequency band spot beam (e.g.,Ka-band spot beam) and a second frequency band spot beam (e.g., Ku-bandspot beam), where the second frequency band spot beam may be concentricwith the first frequency band spot beam. As noted in the foregoingdiscussion, at 808, one or more of the single band feeds 210 previouslyallocated (at 804) to generate a first frequency band spot beam may beexchanged or substituted for a multi-band feed 250 to provide the firstfrequency band spot beam. Because the multi-band feed 250 may generateboth a first frequency band spot beam and a second frequency band spotbeam, the multi-band feed 250 may take the place of select single bandfeeds 210 for providing the first frequency band spot beams. Whenmulti-band feeds 250 take the place of select single band feeds 210 forproviding the first frequency band spot beams, the substitution ofsingle band feeds 210 with multi-band feeds 250 may reduce the number ofsingle band feeds 210 needed for generating first frequency band spotbeams in the overall spot beam layout.

As will be apparent from description of the spot beam layout 400 of FIG.4 and the spot beam layout 700 of FIG. 7, the number of multi-band feeds250 providing dual-band spot beams may be different than the number ofsingle band feeds 210. For the dual-band satellite communication system200 of FIG. 2, the number of multi-band feeds 250 providing thedual-band spot beams may be less than the number of single band feeds210 providing the first frequency spot beams.

Although the foregoing description of embodiments provide for Ka-bandand Ku-band spot beams, the dual-band satellite communication system 200may be configured to provide any dual-band satellite coverage for otherfrequency band pairs. For example, the dual-band satellite communicationsystem 200 may provide dual-band satellite coverage for C-band andKu-band RF signals, or may provide dual-band satellite coverage forKa-band and Q-band RF signals.

In some embodiments, at 802, the method 800 may include determining areflector size 622 based on requirements for both a first beamwidth anda second beamwidth. That is, instead of prioritizing the reflector sizebased on one beamwidth, the reflector size may be based on balancingrequirements of both the first beamwidth and the second beamwidth forachieving a desired spot beam layout. In some other embodiments, themethod 800 may determine a reflector size based on the second beamwidth.

Reference is now made to FIG. 9, which is an illustration of a spot beamlayout overlaid on a map 900 having a coverage perimeter. For example,the coverage perimeter may be the territorial boundaries of China.

The dual-band spot beam layout 900 illustrated in FIG. 9 may be providedby a dual-band satellite communication system 200 of FIG. 2. Forexample, Ka-band spot beams may have a beamwidth of 0.69 detrees andKu-band spot beams may have a beamwidth of 1.12 degrees. In the spotbeam layout 900 of FIG. 9, spot beam locations identified with numbers1, 3, 5, 12, 14, 16, 23, 25, 27, 29, 31, 41, 43, 45, 47, 49, 56, 58, and60 may be dual-band spot beams and may be generated by multi-band feeds250 (FIG. 2). Spot beam locations identified by numbers 2, 4, 6 to 12,13, 15, 17 to 22, 24, 26, 28, 30, 32 to 40, 42, 44, 46, 48, 50 to 55,57, and 59 may be first frequency band spot beams and may be generatedby single band feeds 210 (FIG. 2). Because the dual-band satellitecommunication system 200 may include a shared reflector 260 for thesingle band feeds 210 and the multi-band feeds 250, Ku-band spot beamsmay have a beamwidth that is larger than the beamwidth for Ka-band spotbeams. As illustrated in FIG. 9, fewer Ku-band spot beams than Ka-bandspot beams may be required to provide dual-band coverage for theterritorial boundaries of China.

Although the foregoing description relates to dual-band systems,satellite communication systems may be configured to provide satellitecoverage for three or more frequency bands. For example, in someembodiments, based on the determined reflector size (at 802), the method800 may also include determining a third beamwidth for third frequencyband spot beams. The third beamwidth may be different than the firstbeamwidth and the second beamwidth.

The method 800 may further include allocating one or more feeds in thearray to provide multi-band spot beams. Each of the multi-band spotbeams may include a first frequency band spot beam, a second frequencyband, and a third frequency band spot beam. The first frequency bandspot beam, the second frequency band spot beam, and the third frequencyband spot beam may share a common boresight. That is, each of the spotbeams in the multi-band spot beam may be concentric with other spotbeams in the multi-band spot beam. In some other embodiments, themulti-band spot beam may include a fourth frequency band spot beam orany number of additional band spot beams.

For example, in some embodiments, the first frequency band spot beams,the second frequency band spot beams, and the third frequency band spotbeams may correspond to a frequency band triple. The frequency bandtriple may include one of X-band/Ku-band/Ka-band orKa-band/Q-band/V-band. That is, a multi-band satellite communicationsystem may provide three frequency bands of satellite coverage for anarea circumscribed by a coverage perimeter. Although the frequency bandtriples X-band/Ku-band/Ka-band and Ka-band/Q-band/V-band are described,other frequency band triples may be provided by a multi-band satellitecommunication system.

In the foregoing description, embodiments of methods of providingmulti-band satellite coverage are provided. The embodiments focus onoptimizing a spot beam layout for a first frequency band having a higherfrequency range (e.g., having smaller corresponding beamwidths) prior toproviding a spot beam layout for a second frequency band. For example,the example in FIG. 6 focused on providing an initial first frequencyband spot beam layout 610 prior to providing a dual-band spot beamlayout 670. However, in some other embodiments (e.g., described withreference to FIG. 10), methods of providing dual-band satellite coveragemay focus on optimizing a spot beam layout for a frequency band having alower frequency range (e.g., having larger corresponding beamwidths)prior to providing a spot beam layout for a frequency band having ahigher frequency range (e.g., having smaller corresponding beamwidths).

Reference is now made to FIG. 10, which is a chart 1000 illustrating amethod for providing a spot beam layout in accordance with an embodimentof the present application. Simultaneous reference will be made to FIG.11, which is a spot beam layout 1100 for a satellite coverage perimeterin accordance with an embodiment of the present application. Thesatellite coverage perimeter for the spot beam layout 1100 of FIG. 11may include multiple non-contiguous areas. To aid with describing thespot beam layout 1100, Ku-band spot beams and Ka-band spot beams will beused as example frequency bands.

In FIG. 10, a first portion 1002 may relate to providing a dual-bandspot beam layout 1010. Dual-band spot beams may include a firstfrequency band spot beam (e.g., Ka-band spot beam) and a secondfrequency band spot beam (e.g., Ku-band spot beam). A second portion1008 may relate to providing a first frequency band spot beam layout1080. For example, the first frequency band spot beams may be Ka-bandspot beams. According to the embodiment illustrated in the chart 1000, adual-band spot beam layout 1010 may be generated and/or optimized priorto configuring feeds to provide a Ka-band spot beam layout 1080.

In some embodiments, the dual-band spot beam layout 1010 may be based ondesired locations of dual-band spot beams 1020. High throughput demandareas may be identified. For example, Ku-band throughput demands may beidentified and dual-band spot beams may be provided for providingsatellite coverage to the Ku-band throughput demand areas, resulting inthe dual-band spot beam layout 1010.

To illustrate, referring to FIG. 11, Ku-band high throughput demandareas may be identified and dual-band spot beams may be centered on thehigh throughput demand areas. A first dual-band spot beam 1101 may beprovided at a first high throughput demand area, a second dual-band spotbeam 1102 may be provided at a second high throughput demand area, athird dual-band spot beam 1103 may be provided at a third highthroughput demand area, a fourth dual-band spot beam 1104 may beprovided at a fourth high throughput demand area, and a fifth dual-bandspot beam 1105 may be provided at a fifth high throughput demand area.

In some embodiments, the desired location of dual-band spot beams 1020may be based on Ka-band hotspot requirements 1052. For example, portionsof a coverage area may specifically require Ka-band satellite coverageas a back-up for handling potential spikes in throughput demand. Becausedual-band spot beams may include Ku-band spot beams and Ka-band spotbeams, the dual-band spot beams may be located at such identifiedlocations.

In some embodiments, the dual-band spot beam layout 1010 may be based ona Ku-band spot beam EOC diameter (e.g., beamwidth) and the number ofavailable multi-band feeds 250 (e.g., collectively identified as 1030).For example, the dual-band spot beam layout 1010 may be provided bytaking into consideration whether a dual-band spot beam may be largeenough to provide satellite for an identified high throughput demandarea. If the dual-band spot beam may not be large enough to provide aKu-band spot beam for the given high throughput demand area, thedual-band spot beam layout 1010 may allocate two or more overlappingdual-band spot beams for the given high throughput demand area. Forexample, the first dual-band spot beam 1101, the second dual-band spotbeam 1102, the third dual-band spot beam 1103, and the fourth dual-bandspot beam 1104 are illustrated in FIG. 11 as having overlapping Ku-bandspot beams. Accordingly, in some embodiments, allocating one or morefeeds in the array as multi-band feeds may include configuring the arrayto generate overlapping second frequency band spot beams for a coveragesub-area, where the coverage sub-area encircled by the overlappingsecond frequency band spot beams may be associated with a highthroughput demand area.

In some embodiments, positioning of dual-band spot beams may depend onthe number of available multi-band feeds 250. For example, if only alimited number of multi-band feeds 250 for providing dual-band spotbeams are available, Ku-band spot beam coverage may be selectivelyprovided (e.g., trade-off between satisfying coverage requirementsversus number of multi-band feeds 250 available). For example, if 8portions within a satellite coverage perimeter desire dual-bandcoverage, but only 5 multi-band feeds 250 may be available forgenerating 5 dual-band spot beams, portions within the satellitecoverage perimeter having the “highest” throughput demand may be“ear-marked” as portions on which a multi-band feed 250 may generate adual-band spot beam for.

In some embodiments, a Ku-band spot beam EOC diameter (e.g., beamwidth,identified at 1030) may be based on Ku-band payload or system parameters1052. The Ku-band payload parameters may include high power amplifier(HPA) output power requirements and/or front end noise figurerequirements. In some embodiments, the Ku-band spot beam EOC diametermay be based on Ku-band system parameters, such as coverage requirementsand/or EOC, EIRP, and G/T requirements. In some embodiments, the Ku-bandpayload or system parameters 1052 may include Ku-band user terminalparameters, such as uplink power parameters and satellite dish sizerequirements.

Once a Ku-band spot beam EOC diameter and a number of multi-band feedsis determined for the dual-band spot beam layout 1010, a reflector size1040 may be determined. Based on a required operating frequency (orfrequency range) and the determined Ku-band spot beam EOC diameter, thereflector size 1040 may be determined based at least in part on thehalf-power beamwidth versus reflector diameter relationship illustratedin FIG. 3. Accordingly, based on: (1) selection of location of dual-bandspot beams 1020 and/or (2) Ku-spot beam EOC diameter and/or number ofavailable multi-band feeds 1030, a dual-band spot beam layout 1010 maybe generated and/or optimized.

Although the reflector size 1040 is described as being based on adetermined Ku-band spot beam EOC diameter, in some embodiments, thereflector size 1040 may be determined based on both a first beamwidth(e.g., Ka-band beamwidth) and a second beamwidth (e.g., Ku-bandbeamwidth). That is, the reflector size 1040 may be determined based ona holistic view for providing the spot beam layout 1100.

The second portion 1008 may relate to providing a first frequency bandspot beam layout 1080 (e.g., Ka-band spot beam layout). In someembodiments, the first frequency band spot beam layout 1080 may be basedon the Ka-band spot beam EOC diameter (e.g., beamwidth) and/or thenumber and locations of single band feeds 210 (e.g., collectivelyidentified at 1070). As described, the shared reflector 260 may be usedfor propagating and reflecting Ka-band RF signals (e.g., first frequencyband spot beams) and Ku-band RF signals (e.g., second frequency bandspot beams). Because the reflector size 1040 may have been previouslydetermined, the first beamwidth (e.g., Ka-band beamwidth) may bedetermined. That is, based on the operating frequency (or frequencyrange) of the Ka-band RF signals, a Ka-band spot beam EOC diameter maybe determined based at least in part on the half-power beamwidth versusreflector diameter relationship illustrated in FIG. 3.

In some embodiments, the Ka-band spot beam EOC diameter and/or thenumber/locations of single-band feeds (e.g., collectively identified at1070) may be based on Ka-band system or payload parameters 1060. Forexample, the Ka-band system or payload parameters 1060 may includeKa-band payload parameters such as HPA output requirements and/or frontnoise figure requirements. In some embodiments, the Ka-band system orpayload parameters 1060 may also include Ka-band user terminalparameters, such as uplink power parameters and satellite dish sizerequirements.

In some embodiments, Ka-band hotspot requirements for extra capacitiesmay also be considered for determining the Ka-band beam layout plan1080. Additional Ka-band spot beams may be desired in locations otherthan the identified high throughput demand areas. Accordingly, addedfirst frequency band spot beams (e.g., Ka-band spot beams) may beprovided as a first frequency band spot beam layout 1080. For example,added first frequency band spot beams may be positioned at locationsidentified in FIG. 11 by numbers 6 to 11.

In some embodiments, configuring the array to include single band feedsincludes providing one or more first frequency band spot beamsoverlapping an area encircled by overlapping second frequency band spotbeams to provide dual-band coverage to a high throughput demand area. Aspreviously discussed, the high throughput demand area may already beprovided with overlapping second frequency band spot beams.

Based on the above description of FIGS. 10 and 11, in some embodiments,the chart 1000 illustrates a method for providing a dual-band spot beamlayout 1010 based on identified high throughput demand areas. Thedual-band spot beam layout 1010 provides dual-band spot beams thatinclude second frequency band spot beams (e.g., Ku-band spot beams) andfirst frequency band spot beams (e.g., Ka-band spot beams), where thefirst frequency band spot beams and the second frequency band spot beamsare concentric with each other. Further, the first frequency band spotbeam layout 1080 provides first frequency band spot beams based onlocations other than the identified high throughput demand areas. Thefirst frequency band spot beam layout 1080 may provide supplementalsatellite coverage. Accordingly, as illustrated in FIG. 11, the firstfrequency band spot beam layout 1080 may not comprise first frequencyband spot beams (e.g., Ka-band spot beams) positioned in a contiguousmanner.

Reference is now made to FIGS. 12A to 12D, which are spot beam layouts1200A to 1200D illustrating spot beam placement based on identified highthroughput demand locations, in accordance with embodiments of thepresent application. The spot beams may be provided by the dual-bandsatellite communication system 200 (FIG. 2). Dual-band spot beams mayinclude a first frequency band spot beam (e.g., Ka-band spot beam) and asecond frequency band spot beam (e.g., Ku-band spot beam). In FIGS. 12Ato 12D, the first frequency band spot beams and the second frequencyband spot beams are illustrated as small circles and large circles,respectively.

In some embodiments, high throughput demand areas may be localized alongroads or common travel paths. For example, within an industrial area,there may be high density of satellite user terminals. Further, theremay be high density of satellite user terminals travelling along acommon path. For example, air planes may provide internet service to airpassengers and the air planes may be equipped with satellitetransceivers for transmitting and receiving RF signals. Along a commonflying path, there may be a high density of satellite transceivers. Toensure high throughput demand areas are reliably serviced, methods ofproviding satellite coverage may take into account the identified highthroughput demand areas.

FIG. 12A illustrates a first spot beam layout 1200A having threedual-band spot beams. The dual-band spot beams, identified with numbersfrom 1 to 3, include a first frequency band spot beam (e.g., small spotbeam circle) and a second frequency band spot beam (e.g., large spotbeam circle). The first frequency band spot beam may be a Ka-band spotbeam and the second frequency band spot beam may be a Ku-band spot beam.A high throughput demand area 1210 may represent an area having highdensity of active satellite communication devices.

As illustrated in FIG. 12A, when providing a spot beam layout, threedual-band spot beams may be arranged such that multiple second frequencyband spot beams overlap or intersect at the high throughput demand area1210. For example, three dual-spot beams may be arranged such that theKu-band spot beams intersect at the high throughput demand area 1210.Although the high throughput demand area 1210 is illustrated as a point,the high throughput demand area 1210 may be an enlarged area. Each ofthe Ku-band spot beams may overlap to provide the enlarged area withKu-band satellite coverage. Satellite communication devices locatedwithin the high throughput demand area 1210 may be serviced with Ku-bandsatellite coverage by any of three multi-band feeds 250 (FIG. 2)providing the three intersecting second frequency spot beams of thedual-band spot beams.

Because the first frequency band spot beam (e.g., small spot beamcircle) has a beamwidth that is smaller than the second frequency bandspot beam (e.g., large spot beam circle), first frequency band satellitecoverage may not be provided to the identified high throughput demandarea 1210. To ensure that first frequency spot beams may service theidentified high throughput demand area 1210, arrays of feeds may beconfigured to provide first frequency band spot beams, where the firstfrequency band spot beams may be overlaid on the high throughput demandarea 1210.

FIG. 12B illustrates a second spot beam layout 1200B providingadditional spot beam coverage to the high throughput demand area 1210.The second spot beam layout 1200B may be based on the first spot beamlayout 1200A and may further include a first frequency band spot beam(e.g., identified by number 4) overlaid on the high throughput demandarea 1210. Accordingly, mobile data devices located within the highthroughput demand area 1210 may be serviced with: (1) Ku-band satellitecoverage by any one of three multi-band feeds 250 generating the threeintersecting second frequency band spot beams; and/or (2) Ka-bandsatellite coverage by a single band feed 210 generating an overlaidfirst frequency band spot beam.

In some embodiments, to ensure the high throughput demand area 1210 maybe reliably serviced with first frequency band spot beam coverage (e.g.,Ka-band spot beams), three first frequency band spot beams may beconfigured to overlay the high throughput demand area 1210. FIG. 12Cillustrates a third spot beam layout 1200C that provides additional spotbeam coverage to the high throughput demand area 1210. The third spotbeam layout 1200C is based on the first spot beam layout 1200A andfurther includes three overlaid second frequency spot beams. The threeoverlaid first frequency spot beams may be identified by numbers 4 to 6and may intersect at the identified high throughput demand area 1210. Insome embodiments, each of the first frequency spot beams may overlap toprovide an enlarged area for intersecting second frequency spot beamcoverage. Based on the third spot beam layout 1200C, mobile data deviceslocated within the high throughput demand area 1210 may be serviced withdual-band satellite coverage by: (1) any of three multi-band feeds 250generating the three intersecting dual-band spot beams; and/or (2) anyof three single band feeds 210 generating the three intersecting firstfrequency band spot beams.

In some embodiments, high throughput demand locations may follow definedpaths. FIG. 12D illustrates a fourth spot beam layout 1200D having fourdual-band spot beams. The dual-band spot beams, identified with numbersfrom 1 to 4, include a first frequency band spot beam (e.g., small spotbeam circle) and a second frequency band spot beam (e.g., large spotbeam circle). Similar to FIGS. 12A to 12C, the first frequency band spotbeam may be a Ka-band spot beam and the second frequency band spot beammay be a Ku-band spot beam. To ensure that the high throughput demandpath 1250 may be reliably serviced, methods of providing dual satellitecoverage may take into account the path.

As illustrated in FIG. 12D, four dual-band spot beams, identified withnumbers from 1 to 4, may be arranged such that multiple second frequencyspot beams overlap or intersect along portions of the high throughputdemand path 1250. Satellite communication devices located or travellingalong the high throughput demand path 1250 may be serviced with Ku-bandsatellite coverage by any one of two or more multi-band feeds 250generating intersecting second frequency band spot beams.

Because first frequency band spot beams (e.g., small spot beam circle)has a beamwidth that may be smaller than second frequency band spotbeams (e.g., large spot beam circle), first frequency band satellitecoverage may not be provided to the high throughput demand path 1250.However, arrays of feeds may be configured to provide second frequencyband spot beams overlaid on the high throughput demand path 1250.

Referring still to FIG. 12D, the fourth spot beam layout 1200D furtherincludes first frequency band spot beams (e.g., identified by numbers 5to 9) successively overlaid on the high throughput demand path 1250. Insome embodiments, adjacent first frequency band spot beams may overlap.Thus, satellite communication devices located along the high throughputdemand path 1250 may be serviced with: (1) Ku-band satellite coverage byany one of two or more multi-band feeds 250 generating intersectingsecond frequency band spot beams; and/or (2) Ka-band satellite coverageby at least one single band feed 210 generating first frequency spotbeams overlaid on the high throughput demand path 1250. Accordingly,overlapping Ku-band spot beams may provide Ku-band satellite coverageservice along the high throughput demand path 1250, and Ka-band spotbeams overlaid along the high throughput demand path 1250 may provideKa-band satellite coverage service.

As will be apparent from the description of the present application,embodiments of the method and satellite may provide dual-band satellitecoverage for identified high throughput areas or paths while minimizingthe number of multi-band feeds in a dual-band satellite communicationsystem. That is, an array of feeds for providing spot beams may compriseboth single band feeds and multi-band feeds. Multi-band feeds may costmore than single band feeds. Thus, by minimizing the number ofmulti-band feeds to be used, costs of the dual-band satellitecommunication system may be reduced.

Further, embodiments of methods for providing dual-band satellitecoverage described in the present application may provide overlappingspot beams to identified high throughput areas or paths for boastingreliability and/or quality of satellite coverage service. For example,in some embodiments, allocating one or more feeds in an array of feedsas multi-band feeds may include configuring the array to provideoverlapping second frequency band spot beams (e.g., Ku-band spot beams)for a coverage sub-area. The coverage sub-area encircled by theoverlapping second frequency band spot beams may be associated with ahigh throughput demand area or path. Further, in some embodiments,configuring the array to include single band feeds may include providingone or more first frequency band spot beams (e.g., Ka-band spot beams)overlapping the area encircled by the overlapping second frequency bandspot beams (see e.g., spot beam layout embodiments in FIGS. 12C and12D).

Digital Channelizing Dual-Band Satellite Communication System

In some embodiments, a satellite communication system may provideflexibility to ground terminals capable of uplink and downlink usingboth Ka-band and Ku-band frequencies. Reference is now made to FIG. 13A,which is a block diagram of a digital channelizing dual-bandcommunication satellite system 1300A in accordance with an embodiment ofthe present application. Like reference numerals are used in FIG. 13A todenote like elements and features.

The digital channelizing dual-band communication satellite system 1300Amay be based on the dual-band communication satellite system 200 of FIG.2 and may further include a digital channelizer 1380 for routing signalsamong payloads for different frequency bands. For example, the digitalchannelizing dual-band communication satellite system 1300A may includea Ka-band payload 1312, a Ku-band payload 1352, and an array of feedsfor providing spot beams for a satellite coverage perimeter. The arrayof feeds may include a plurality of single band feeds 210 and multi-bandfeeds 250. The single band feeds 210 may generate first frequency spotbeams, such as Ka-band spot beams. Although only two single band feeds210 are illustrated, the dual-band communication satellite system 200may include any number of single band feeds 210.

In some embodiments, the multi-band feeds 250 may generate dual-bandspot beams. Each dual-band spot beam may include a first frequency bandspot beam and a second frequency band spot beam. The second frequencyband spot beam may be concentric with the first frequency band spotbeam. That is, the first frequency band spot beam may share a boresightwith the second frequency band spot beam. In some embodiments, the firstfrequency band spot beam may be a Ka-band spot beam and the secondfrequency band spot beam may be a Ku-band spot beam. The digitalchannelizing dual-band communication satellite system 1300A may includea shared reflector 260.

As described, the digital channelizing dual-band communication satellitesystem 1300A may also include a digital channelizer 1380 and a pluralityof receivers 1385 (e.g., low noise amplification and frequencyconversion receivers). Thus, the digital channelizer 1380 may be at theKa-payload 1312 front end and the Ku-payload 1352 front end for routingreceived signals from user or ground terminals. For example, a forwardlink (e.g., gateway to user terminal) and a return link (e.g., userterminal to gateway) may be routed to either of the Ka-payload 1312 orthe Ku-payload 1352. Accordingly, the forward link and/or return linkmay be routed to either of first frequency band spot beams or secondfrequency band spot beams.

With increasing throughput demands on satellite systems, Ka-bandpayloads for providing spot beams may be increasingly useful. However,heavy rain in coastal regions of countries such as China, India,Singapore, Malaysia, or Indonesia (e.g., such as ITU Region 3 countries)may cause RF signal links operating in the Ka-band of frequencies todrop or to be severed. Ku-band frequencies may be useful for mitigatingfading effects caused by heavy rain or other weather conditions.Accordingly, a digital channelizing dual-band communication satellitesystem 1300A providing spot beam layouts for two or more frequency bandsmay facilitate data paths among alternate frequency bands to counteractunwanted weather related effects. The digital channelizer 1380 mayfacilitate inter-frequency band connectivity among spot beams in a spotbeam layout.

Reference is now made to FIG. 13B, which is a system diagramillustrating Ku-band/Ka-band links for rain fade mitigation. A satellitesystem 1300B may include a digital channelizing dual-band communicationsatellite system 1300A, a gateway terminal 1394 and a user terminal1396. Data transmission between the gateway 1394 and the user terminal1396 may be provided using “two hops” including a forward hop and areturn hop. The forward hop may include propagation of a signal from thegateway 1394 to the user terminal 1396. For example, the forward hop mayinclude the forward uplink (e.g., gateway 1394 to satellite 1300A) andthe forward downlink (e.g., satellite 1300A to user terminal 1396). Thereturn hop may include propagation of a signal from the user terminal1396 to the gateway 1394. For example, the return hop may include thereturn uplink (e.g., user terminal 1396 to satellite 1300A) and thereturn downlink (e.g., satellite 1300A to gateway 1394). Both Ku-bandand Ka-band frequencies may include forward and return links.

Described another way, in some embodiments, the satellite system 1300Bmay include gateway links 1390, where the gateway links 1390 includeforward uplink and return downlink paths for both Ka-band and Ku-bandfrequencies between the gateway terminal 1394 and the digitalchannelizing dual-band communication satellite system 1300A. Similarly,the satellite system 1300B may include user links 1392, where the userlinks 1392 include forward downlink and return uplink paths 1392 forboth Ka-band and Ku-band frequencies between the user terminal 1396 andthe digital channelizing dual-band communication satellite system 1300A.The digital channelizing dual-band communication satellite system 1300Amay provide one or more Ka/Ku-band spot beam layouts 1398 for providingdual-band satellite coverage.

In FIG. 13B, the user terminal 1396 may be located at the center of adual-band spot beam. If the user terminal 1396 were capable of operatingon Ka-band and Ku-band frequencies, during heavy rain or any otherweather condition that may cause degradation or severance of a satellitelink, the digital channelizing dual-band communication satellite system1300A may be able to route RF signals from one of the frequency bands(e.g., Ka-band or Ku-band) to another frequency band (e.g., Ku-band orKa-band) to mitigate undesirable effects from extreme weather.

In some embodiments, the digital channelizer 1380 (FIG. 13A) may, forexample, provide beam connection routing capability according to any oneof the following example combinations: (1) Ku-band uplink, Ku-banddownlink; (2) Ka-band uplink, Ka-band downlink; (3) Ku-band uplink,Ka-band downlink; and/or (4) Ka-band uplink, Ku-band downlink.

In some other embodiments, the digital channelizer 1380 may facilitateuplink transmission of data using a first frequency band spot beam(e.g., Ka-band spot beam) and facilitate downlink transmission of asubset or portion of data using the first frequency band spot beam(e.g., Ka-band spot beam) and further facilitate a remaining portion ofdata using a second frequency band spot beam (e.g., Ku-band spot beam).The configuration of uplink and downlink transmission of data describedabove may be useful when a downlink capacity of a first frequency bandspot beam may be near full capacity. Thus, a second frequency band spotbeam may assist for facilitating downlink transmission and therebyexpanding overall satellite transmission capacity. Accordingly, thedigital channelizer 1380 may, for example, provide beam connectionrouting capability according to any one of the following examplecombinations: 1) Ku-band uplink, partial Ku-band downlink and partialKa-band downlink; and/or 2) Ka-band uplink, partial Ka-band downlink andpartial Ku-band downlink.

In a further illustrating example, a radio frequency signal may beuplinked at a first frequency band (e.g., Ka-band frequency). The radiofrequency signal may then be downlinked at a second frequency band(e.g., Ku-band frequency). The first frequency may be different than thesecond frequency (see e.g., example embodiments in U.S. patentapplication Ser. No. 13/569,980, published as U.S. Patent ApplicationPublication No. 2014/0045420 A1). Accordingly, in some embodiments, thedigital channelizer 1380 (FIG. 13) may facilitate data uplink and datadownlink on a first frequency band and a second frequency band,respectively, using a multi-band feed 250 that generates a dual-bandspot beam.

In some embodiments, user terminals 1396 may be equipped to operate withone frequency band. For example, legacy vehicles may still be equippedwith satellite equipment for one of the Ka-band or the Ku-band.Accordingly, the digital channelizing dual-band communication satellitesystem 1300A may adaptively determine what frequency band a userterminal 1396 may be capable of sending and receiving RF signals withand subsequently facilitate data transmission using a frequency bandthat may be supported by the user terminal 1396.

It will be apparent that embodiments of digital channelizing dual-bandcommunication satellite systems 1300A described in the presentapplication may be able to adaptively facilitate transmission andreceipt of RF signals using frequencies of multiple frequency bands. Inone embodiment, to mitigate undesirable effects caused by heavy rain orother weather conditions on Ka-band frequencies, embodiments of digitalchannelizing dual-band communication satellite systems 1300A may routesignals to Ku-band frequencies, and maintain reliable communicationlinks. Further, it will be apparent that embodiments of digitalchannelizing dual-band communication satellite systems 1300A mayadaptively route signals using frequency bands that may be supported byground or user terminals. Thus, the digital channelizing dual-bandcommunication satellite systems 1300A may be capable of transmitting andreceiving signals to and from a wider range of user terminals havingdifferent frequency band capabilities.

Frequency Reuse Plans

In a spot beam layout, spot beams may experience co-channel interferencefrom contiguous or adjacent spot beams in a spot beam layout. Forexample, signals within a first spot beam may experience interferencefrom an adjacent spot beam operating within the same frequency band. Insome embodiments, however, co-channel interference between contiguous oradjacent spot beams may be mitigated using a “multi-color” frequencyreuse scheme.

Reference is now made to FIG. 14A, which is an illustration of a Ka-band4-color and a Ku-band 8-color reuse frequency plan for a dual Ka/Ku-bandspot band layout. For the Ka-band, a standard 4-color frequency reuseplan may be adopted. For the Ku-band, up to an 8-color reuse scheme maybe adopted to compensate for any performance degradations that may becaused by use of multi-band feeds.

FIG. 14B is a spot beam layout of FIG. 4 illustrated using a Ka-band4-color and a Ku-band 8-color reuse frequency plan of FIG. 14A.Dual-band spot beams may be provided by multi-band feeds 250. Dual-bandspot beams may be illustrated and identified in FIG. 14B with numbers10, 12, 14, 27, 29, and 31.

As illustrated, co-channel interference may be mitigated by using a4-color reuse frequency plan for the Ka-band spot beams provided bysingle band feeds 210 (e.g., Ka-band spot beams numbered from 1 to 40).For example, four colors may be represented by the letters A to D (FIGS.14A and 14B). As illustrated in FIG. 14B, adjacent Ka-band spot beamsmay utilize a different color in the color frequency reuse plan. Anadjacent spot beam may utilize a different frequency range andpolarization. Specifically, spot beams 1 to 8, 17 to 24, and 33 to 40may be represented by alternating colors identified by A and B. Spotbeams 9 to 16 and 25 to 32 may be represented by alternating colorsidentified by C and D.

Similarly, 8 colours may be represented by the letters E to L (FIGS. 14Aand 14B). As illustrated in FIG. 14B, adjacent Ku-band spot beams mayutilize a different color in the color frequency reuse plan.Specifically, the second frequency band spot beam in the dual-band spotbeam identified by the number 10 may include a Ku-band spot beamrepresented by a color designated by the letter E. The second frequencyband spot beam in the dual-band spot beam identified by the number 12may include a Ku-band spot beam represented by a color designated by theletter F. The second frequency band spot beam in the dual-band spot beamidentified by the number 14 may include a Ku-band spot beam representedby a color designated by the letter I. The second frequency band spotbeam in the dual-band spot beam identified by the number 27 may includea Ku-band spot beam represented by a color designated by the letter G.The second frequency band spot beam in the dual-band spot beamidentified by the number 29 may include a Ku-band spot beam representedby a color designated by the letter H. Further, second frequency bandspot beam in the dual-band spot beam identified by the number 31 mayinclude a Ku-band spot beam represented by a color designated by theletter J.

In the illustrated 4-color Ka-band and 8-color Ku-band frequency reusescheme, Ku-band spot beams reuse 235 MHz of usable bandwidth out of the1 GHz Ku-band downlink bands, thereby reducing the co-channelinterference in a 4-color frequency reuse scheme.

Reference is now made to FIG. 15, which is an example Ku-band andKa-band 4-color frequency reuse plan for a dual-band communicationsatellite system in accordance with an embodiment of the presentapplication. The colors of the frequency reuse plan may be representedby the letters A to H. For example, Ku-beams may adopt a 4-colorfrequency reuse scheme for the Ku-extended bands. Even though the usablefrequency band for each color may be 118 MHz, there may be nocross-polarization interference present. The frequency reuse plan mayalso increase the overall carrier-to-noise ratio and improve satellitesystem throughput.

Reference is now simultaneously made to FIGS. 16A and 16B. FIG. 16A isan illustration of a Ka-band 2-color and a Ku-band 4-color frequencyreuse plan for a dual Ka/Ku-band spot band layout in accordance with anembodiment of the present application. FIG. 16B is a spot beam layout ofFIG. 11 illustrated using the Ka-band 2-color and the Ku-band 4-colorfrequency reuse plan of FIG. 16A. As previously described with referenceto FIG. 11, dual-band spot beams may be provided and centered on highthroughput demand areas, identified by numbers 1 to 5. As illustrated,the dual-band spot beams centered on numbers 1 to 4 may each provide asecond frequency band spot beam (e.g., Ku-band spot beam) and the secondfrequency band spot beam from each of the dual-band spot beamsidentified by numbers 1 to 4 may be adjacent and may overlap.

In some embodiments, co-channel interference may be mitigated by usingthe Ka-band 2-color and Ku-band 4-color frequency reuse plan. Forexample, 2 colors may be represented by letters A and B for the Ka-bandand 4 colors may be represented by letters C to F. To mitigateco-channel interference among the contiguous first frequency band spotbeams, the color frequency re-use plan illustrated in FIG. 16A may beemployed. That is, adjacent spot beams may utilize a different frequencyrange and polarization.

Further, in the spot beam layout of FIGS. 11 and 16B, a first frequencyband spot beam layout (e.g., Ka-band spot beam layout) includesnon-contiguous Ka-band spot beams. A frequency reuse scheme utilizingfewer colors (e.g., 2-color) may be adapted.

Reference is now made to FIG. 17, which is a frequency plan formitigating an uplink/downlink frequency spectrum imbalance issue for adual Ka/Ku-band satellite communication system in accordance with anembodiment of the present application. The Ka-band frequency spectrummay have greater frequency resource compared to the Ku-band frequencyspectrum. The digital channelizing dual-band satellite communicationsystem 1300A of FIG. 13 may mitigate the aforementioned uplink/downlinkfrequency spectrum imbalance issue.

For example, in the ITU Region-3, the total downlink frequency spectrumfor the standard and extended Ku-band may be 1 GHz per polarization. Incontrast, the uplink frequency spectrum may comprise 750 MHz perpolarization. Thus, if the Ku-band frequencies are designed to employsymmetric uplink/downlink traffic flow, a 250 MHz sub-range shortage mayexist for each polarization. With the digital channelizing dual-bandsatellite communication system 1300A of FIG. 13, however, a 250 MHzfrequency sub-range from the Ka-band spectrum may be allocated to theKu-band uplink range of frequencies to balance the additional 250 MHzuser downlink frequency sub-range for the Ku-band. Thus, the dual-bandfrequency plan illustrated in FIG. 17 may mitigate the aforementioneduplink/downlink frequency spectrum imbalance issue. That is, in someembodiments, the first frequency band may be the Ka-band and the secondfrequency band may be the Ku-band. The Ku-band may be configured toprovide symmetric uplink/downlink throughput. Accordingly, digitallychannelizing the spectrum of dual-band frequencies may includeallocating a range of frequencies from an uplink Ka-band for use as anuplink Ku-band of frequencies.

Other Example Dual-Band Communication Satellite Systems

The number of feeds that may be placed near a parabolic reflector focuspoint may be limited. For example, if the number of feeds placed near aparabolic reflector focus point is large, significant distortions tobeam gain may be introduced. In addition, cross-polarization performanceissues may result. Accordingly, in some embodiments, a dual-bandcommunication satellite system having numerous feeds may include two ormore reflectors for propagating and receiving signals from the numerousfeeds.

Reference is now made to FIG. 18, which is a block diagram of adual-band communication satellite system 1800 in accordance with anotherembodiment of the present application. The dual-band communicationsatellite system 1800 may include a Ka-band payload 1812 and a Ku-bandpayload 1852. The dual-band communication satellite system 1800 may alsoinclude an array of feeds for providing spot beams for a satellitecoverage perimeter. The array of feeds may include a plurality of singleband feeds 1810 and multi-band feeds 1850. The single band feeds 1810may be similar to the single band feeds 210 described with reference toFIG. 2. The multi-band feeds 1850 may be similar to the multi-band feeds250 described with reference to FIG. 2.

The dual-band communication satellite system 1800 may also include adual-band reflector 1860 and a single-band reflector 1870. In someembodiments, the multi-band feeds 1850 may transmit and receive signalsusing the dual-band reflector 1860. That is, the dual-band reflector1860 may propagate and receive RF signals for both Ka-band frequenciesand Ku-band frequencies. It will be appreciated that the dual-bandreflector 1860 may be for any other frequency bands.

The single-band reflector 1870 may propagate and receive RF signals forKa-band frequencies. Accordingly, in some embodiments, single band feeds1810 (e.g., Ka-band feeds) may be grouped into a cluster and maytransmit and receive signals using the single-band reflector 1870.Multi-band feeds 1850 may be grouped into a different cluster and maytransmit and receive signals using the dual-band reflector 1860. In someembodiments, the dual-band reflector 1860 and the single band reflector1870 may have different sizes. That is, where the dual-bandcommunication satellite system 1800 includes two or more sharedreflectors, a shared reflector in the two or more shared reflectors maybe different in size than another shared reflector in the two or moreshared reflectors.

In some embodiments, the dual-band communication satellite system 1800may include one or more single band reflectors 1870. That is, one ormore first shared reflectors may be for the plurality of single bandfeeds 1810. In some embodiments, the dual-band communication satellitesystem 1800 may include one or more dual-band reflectors 1860. That is,one or more second shared reflectors may be for the plurality ofmulti-band feeds 1850. In some embodiments, the one or more first sharedreflectors may be different in size than the one or more second sharedreflectors.

Reference is now made to FIG. 19, which is another example spot beamlayout 1900 for a satellite coverage perimeter 1980 in accordance withan embodiment of the present application. The spot beam layout 1900 mayinclude spot beams for Ka-band and Ku-band frequencies. The spot beamlayout 1900 may be provided by the dual-band communication satellitesystem 1800 described with reference to FIG. 18. The desired satellitecoverage perimeter 1980 is illustrated by dashed lines and may be arectangular perimeter. Although the satellite coverage perimeter 1980 isillustrated as a rectangular perimeter, the desired satellite coverageperimeter 1980 may be any other shape or combination of shapes.

Similar to the spot beam layout 700 described with reference to FIG. 7,the spot beam layout 1900 of FIG. 19 may include first frequency bandspot beams and second frequency band spot beams. For example, firstfrequency band spot beams may be Ka-band spot beams and second frequencyband spot beams may be Ku-band spot beams. The spot beam layout 1900 ofFIG. 19 may be generated by a plurality of single band feeds 1810 (FIG.18) and multi-band feeds 1850 (FIG. 18). The multi-band feeds 1850 mayeach generate a first frequency band spot beam (e.g., Ka-band spot beam)and a second frequency band spot beam (e.g., Ku-band spot beam).

Similar to the spot beam layout 700 illustrated in FIG. 7, in the spotbeam layout 1900 of FIG. 19, three multi-band feeds 1850 may generatethree dual-band spot beams. For example, a multi-band feed 1850 maygenerate a dual-band spot beam 1915 indicated at a location identifiedby the number 15. The dual-band spot beam 1915 may include a firstfrequency band spot beam 1915 a (small circle) and a second frequencyband spot beam 1915 b (large circle). In FIG. 19, three dual-band spotbeams are illustrated and indicated at locations identified by thenumbers 9, 15, and 28. For example, a first dual-band spot beam 1909, asecond dual-band spot beam 1915, and a third dual-band spot beam 1928are illustrated.

In addition to the three illustrated dual-band spot beams in FIG. 19,the spot beam layout 1900 may also include a plurality of additionalfirst frequency band spot beams (e.g., Ka-band spot beams). A pluralityof single band feeds 1810 may generate the plurality of additional firstfrequency band spot beams at locations indicated by numbers 1 to 8, 10to 14, 16 to 27, and 29 to 40. For ease of illustration, three firstfrequency band spot beams generated by single band feeds 1810 have beenidentified, such as fourth spot beam 1924, fifth spot beam 1925, andsixth spot beam 1926.

In the spot beam layout 1900 of FIG. 19, the first frequency band spotbeams (e.g., Ka-band spot beams) generated by single band feeds 1810 mayhave a different beamwidth than the first frequency band spot beamsgenerated by multi-band feeds 1850. For example, Ka-band spot beamsgenerated by single band feeds 1810 may have a 0.8 degrees beamwidth,while Ka-band spot beams generated by multi-band feeds 1850 may have a1.4 degrees beamwidth. In some embodiments, as the dual-band reflector1860 (FIG. 18) and the single-band reflector 1870 (FIG. 18) may havedifferent sizes, some Ka-band spot beams generated by multi-band feeds1850 may have a different beamwidth than another Ka-band spot beamgenerated by single band feeds 1810. For example, a Ka-band spot beam1915 a generated by a multi-band feed 1850 may have a 1.4 degreesbeamwidth while a Ka-band spot beam 1924 generated by a single band feed1810 may have a 0.8 degrees beamwidth. Accordingly, the spot beam layout1900 of FIG. 19 may include multiple Ka-band spot beams having twodifferent beamwidths.

In some embodiments, Ka-band beamwidths may be derived based on theKa-band system parameters, such as EOC, EIRP, and G/T requirementsand/or targeted user or ground terminal size. Once Ka-band beamwidthsare determined, respective reflector sizes, such as reflector sizes fordual-band reflectors 1860 and single-band reflectors 1870, may bedetermined based at least in part on the half-power beamwidth versusreflector diameter relationship illustrated in FIG. 3.

Reference is now made to FIG. 20, which is a chart 2000 illustratingdetails for providing spot beam layouts in accordance with anotherembodiment of the present application. Similar to the chart describedwith reference to FIG. 6, a first portion 2002 may relate to a Ka-bandspot beam layout plan 2010 and a second portion 2008 may relate to adual Ku/Ka-band spot beam layout plan 2070.

Similar to the chart described with reference to FIG. 6, in someembodiments, the first frequency band spot beam layout 2010 may be basedon Ka-band system parameters 2030, such as coverage requirements and/orEOC, EIRP, and G/T requirements. In some embodiments, the firstfrequency band spot beam layout 2010 may also be based on a firstfrequency band beamwidth, such as a first Ka-band spot beam EOC diameter2020. The first Ka-band spot beam EOC diameter 2020 may be associatedwith single-band feeds 1810 (FIG. 18). For example, the first Ka-bandspot beam EOC diameter 2020 may be 0.8 degrees (see e.g., FIG. 19). Oncethe first Ka-band spot beam EOC diameter 2020 is determined, asingle-band reflector 1870 size may be determined based at least in parton the half-power beamwidth versus reflector diameter relationshipillustrated in FIG. 3.

As described, the second portion 2008 may relate to a dual Ku/Ka-bandspot beam layout plan 2070. Similar to the chart 600 illustrated withreference to FIG. 6, the dual Ku/Ka-band spot beam layout plan 2070 maybe based on a Ku-band spot beam EOC diameter and a determination of thenumber and sequence order of multi-band feeds (collectively identifiedin FIG. 20 as 2060). The Ku-band spot beam EOC diameter and thedetermination of the number and sequence order of multi-band feeds maybe based on Ku-band system parameters 2050. The Ku-band systemparameters 2050 may be similar to the Ku-band system parameters 650identified with reference to FIG. 6.

Further, the dual Ku/Ka-band spot beam layout plan 2070 may also bebased on a second Ka-band spot beam EOC diameter 2024. The secondKa-band spot beam EOC diameter 2024 may also be determined based onKa-band system parameters 2030, such as coverage requirements and/orEOC, EIRP, and G/T requirements. For example, the second Ka-band spotbeam EOC diameter 2024 may be 1.4 degrees (see e.g., FIG. 19).Accordingly, as was illustrated in FIG. 19, Ka-band spot beams generatedby single-band feeds 1810 (FIG. 18) may have a different beamwidth thanKa-band spot beams generated by multi-band feeds 1850 (FIG. 18).

Referring still to FIG. 20, the dual Ku/Ka-band spot beam layout plan2070 may be based on both the second Ka-band spot beam EOC diameter 2024and Ku-band variables (collectively identified as 2060). Similarly, adual-band reflector 1860 (FIG. 18) may have a size based on both thesecond Ka-band spot beam EOC diameter 2024 and Ku-band variables(collectively identified as 2060).

In some embodiments, a beamwidth for a second frequency band spot beam(e.g., Ku-band spot beam) may be determined after the dual-bandreflector size 2026 is determined. That is, the dual-band reflector size2026 may not be determined based on a beamwidth for the second frequencyband spot beam (e.g., Ku-band spot beam).

Although one single-band reflector 1870 (FIG. 18) having a Ka-bandreflector size 2022 and one dual-band reflector 1860 (FIG. 18) having adual-band reflector size 2026 is described with reference to FIG. 20,embodiments of the present application may include two or moresingle-band reflectors 1870 and two or more dual-band reflectors 1860.

In some embodiments where the satellite coverage perimeter may includenon-contiguous areas (see e.g., spot beam layout 1100 described withreference to FIG. 11), a spot beam layout may have first frequency bandspot beams (e.g., Ka-band spot beams) generated by single band feeds1810 (FIG. 18) with a different beamwidth than first frequency band spotbeams (e.g., Ka-band spot beams) generated by multi-band feeds 1850(FIG. 18). As an example, a spot beam layout that may be similar to thespot beam layout 1100 of FIG. 11 may include multiple Ka-band spot beamshaving two different beamwidth sizes. For example, a first group ofKa-band spot beams (illustrated in FIG. 11 at locations 1 to 5)generated by multi-band feeds 1850 may have a different beamwidth thanKa-band spot beams (illustrated in FIG. 11 at locations 6 to 11)generated by single band feeds 1010.

Based on the foregoing examples, a dual-band communication satellitesystem may include two or more reflectors. A reflector or a group ofreflectors may be sized for a cluster of feeds. One cluster of feeds mayinclude Ka-band feeds and a second cluster of feeds may also includeKa-band feeds. Each cluster of feeds may propagate and receive RFsignals from differently sized reflectors. Accordingly, in someembodiments, a dual-band communication satellite system may generate aplurality of Ka-band spot beams, where some Ka-band spot beams may havea beamwidth different than a second group of Ka-band spot beams. Thedifferent beamwidths may be generated as long as each group of Ka-bandspot beams meet Ka-band system parameters, such as EOC, EIRP, and G/Trequirements.

Example embodiments of the present disclosure are not limited to anyparticular type of satellite or antenna.

The various embodiments presented above are merely examples and are inno way meant to limit the scope of this application. Variations of theinnovations described herein will be apparent to persons of ordinaryskill in the art, such variations being within the intended scope of thepresent application. Additionally, the subject matter described hereinand in the recited claims intends to cover and embrace all suitablechanges in technology.

1. A satellite system for providing dual-band satellite coverage using aspot beam layout for a satellite coverage perimeter, the systemcomprising: an array of feeds, the array including: a plurality ofsingle band feeds, the single band feeds generating first frequency bandspot beams, and one or more multi-band feeds each generating a firstfrequency band spot beam and a second frequency band spot beamconcentric with the first frequency band spot beam, the first frequencyband spot beam having a different beamwidth than the second frequencyband spot beam, wherein the number of multi-band feeds is different thanthe number of single band feeds; and a shared reflector for the array offeeds.
 2. The system of claim 1, wherein the shared reflector is for atleast one single band feed and at least one multi-band feed.
 3. Thesystem of claim 1, wherein the shared reflector is for each of theplurality of single band feeds and for each of the one or moremulti-band feeds in the array of feeds.
 4. The system of claim 1,wherein the system includes two or more shared reflectors, and whereineach shared reflector is the same size as another shared reflector inthe two or more shared reflectors, and wherein a first shared reflectoris for the plurality of single band feeds and a second shared reflectoris for the one or more multi-band feeds.
 5. The system of claim 1,wherein the system includes two or more shared reflectors, and whereinone or more first shared reflectors are for the plurality of single bandfeeds and one or more second shared reflectors are for the one or moremulti-band feeds, and wherein the one or more first shared reflectorsare different in size than the one or more second shared reflectors. 6.The system of claim 1, wherein the system includes two or more sharedreflectors, and wherein a first shared reflector in the two or moreshared reflectors is different in size than another shared reflector inthe two or more shared reflectors.
 7. The system of claim 1, wherein thefirst frequency band spot beam has a first beamwidth and the secondfrequency band spot beam has a second beamwidth, and wherein the sharedreflector has a reflector size, and wherein the reflector size is basedon at least one of the first frequency band spot beam or the secondfrequency band spot beam.
 8. The system of claim 1, wherein the singleband feeds are Ka frequency band feeds and the multi-band feeds are dualKa/Ku frequency band feeds.
 9. The system of claim 1, wherein the numberof multi-band feeds is less than the number of single band feeds. 10.The system of claim 1, further comprising a digital channelizer tochannelize a digitized spectrum of dual-band frequencies to route uplinkor downlink signal transmissions to one of a first frequency band or asecond frequency band, the spectrum of dual-band frequencies includingfrequencies of the first frequency band and frequencies of the secondfrequency band.
 11. The system of claim 1, wherein the one or moremulti-band feeds provides multi-band spot beams, each of the multi-bandspot beams including a first frequency band spot beam, a secondfrequency band spot beam, and a third frequency band spot beam, andwherein each of the first frequency band spot beam, the second frequencyband spot beam, and the third frequency band spot beam being concentricwith another of first frequency band spot beam, the second frequencyband spot beam, and the third frequency band spot beam.
 12. A method forproviding dual-band satellite coverage using a spot beam layout for asatellite coverage perimeter, the method comprising: determining areflector size for an array of feeds, the array generating firstfrequency band spot beams, each first frequency band spot beam having afirst beamwidth; configuring the array to include single band feeds togenerate the first frequency band spot beams for the satellite coverageperimeter; based on the determined reflector size, determining a secondbeamwidth for second frequency band spot beams, the second beamwidthbeing different than the first beamwidth; and allocating one or morefeeds in the array as multi-band feeds to generate dual-band spot beams,each of the dual-band spot beams including a first frequency band spotbeam and a second frequency band spot beam concentric with the firstfrequency band spot beam, wherein the number of multi-band feeds isdifferent than the number of single band feeds.
 13. The method of claim12, wherein the number of the multi-band feeds providing the dual-bandspot beams is less than the number of the single band feeds providingthe first frequency spot beams.
 14. The method of claim 12, whereindetermining the second beamwidth is based on the determined reflectorsize and a second frequency band EOC peak-to-edge gain deltarequirement.
 15. The method of claim 12, wherein the first frequencyband spot beams are Ka frequency band spot beams, and wherein the secondfrequency band spot beams are Ku frequency band spot beams.
 16. Themethod of claim 12, wherein the first frequency band spot beams and thesecond frequency band spot beams correspond to a frequency band pair,and wherein the frequency band pair is one of C-band/Ku-band orKa-band/Q-band.
 17. The method of claim 12 further comprising: based onthe determined reflector size, determining a third beamwidth for thirdfrequency band spot beams, the third beamwidth being different than thefirst beamwidth and the second beamwidth; and allocating one or morefeeds in the array to generate multi-band spot beams, each of themulti-band spot beams including a first frequency band spot beam, asecond frequency band spot beam, and a third frequency band spot beam,and wherein each of the first frequency band spot beam, the secondfrequency band spot beam, and the third frequency band spot beam beingconcentric with another of the first frequency band spot beam, thesecond frequency band spot beam, and the third frequency band spot beam.18. The method of claim 17, wherein the first frequency band spot beams,the second frequency band spot beams, and the third frequency band spotbeams correspond to a frequency band triple, and wherein the frequencyband triple is one of X-band/Ku-band/Ka-band or Ka-band/Q-band/V-band.19. The method of claim 12, wherein configuring the array to generatethe first frequency band spot beams includes configuring the array tomaximize the area within the satellite coverage perimeter having firstfrequency band spot beam coverage.
 20. The method of claim 12, whereinallocating one or more feeds in the array as multi-band feeds includesconfiguring the array to generate overlapping second frequency band spotbeams for a coverage sub-area, wherein the coverage sub-area isassociated with a high throughput demand area.
 21. The method of claim20, wherein configuring the array to include single band feeds includesgenerating one or more first frequency band spot beams overlapping thecoverage sub-area encircled by the overlapping second frequency bandspot beams to provide dual-band coverage to the high throughput demandarea.
 22. The method of claim 12, wherein the second beamwidth is largerthan the first beamwidth, and wherein allocating one or more feeds inthe array to generate dual-band spot beams comprises: identifyingportions within the coverage perimeter requiring dual-band coverage; andselecting non-adjacent feeds in the array as multi-band feeds togenerate the required dual-band coverage for the coverage perimeter. 23.The method of claim 12, further comprising digitally channelizing aspectrum of dual-band frequencies to route uplink or downlink signaltransmissions to one of a first frequency band or a second frequencyband, the spectrum of dual-band frequencies including frequencies of thefirst frequency band and frequencies of the second frequency band. 24.The method of claim 23, wherein the first frequency band is the Ka-bandand the second frequency band is the Ku-band, and wherein the Ku-band isconfigured to provide symmetric uplink/downlink throughput, and whereindigitally channelizing the spectrum of dual-band frequencies includesallocating a range of frequencies from an uplink Ka-band for use as anuplink Ku-band of frequencies.